Fiendslayer Paladin and Graceblade Artisan both wield swords at an angle where the light either reflects off them or is shining from within in a way that makes them look like lightsabers.

Cruising through our archives I see one topic with some possible ideas here:
Anafenza, Kin-Tree Spirit could maybe have an argument made for a lightsaber, but I think the point in the thread was more force-ghost oriented
Battle Mastery is very shiny.

What other instances of this do people know about?

Now I want to build this deck.







USE THE FORCE, LUKE

Looking at those little pictures, my first guess for both examples is that those are normal, metal blades charged with magical energy. I think your call on Anafenza is right. Battle Mastery could really be a number of things.

I'd be totally cool with more energy blades in M:TG. They can't be lightsabers, obviously. Those or technological, and have a franchise-specific look and lore. But blades consisting of magical energy? Bring 'em on. I feel similarly about lasers. The term "laser" evokes sci-fi, but a beam of light is a perfectly acceptable fantasy weapon. It's the perfect weapon for an angel. Or certain dragons. Call them, beams of "radiance", or solar rays, or shafts of light if that helps. Just don't throw out the light-weapon concept because you associate it with another genre.

Actually, now I want to see a pulp fantasy work with a "radio death ray" spewing dragon.

Not exactly lightsabers, but here are two famed Jedi masters.

Kitsune Dawnblade
Markov Blademaster
Odric, Lunarch Marshal and Odric, Master Tactician
Vow of Lightning (Darth Maul?)
Flaming Sword, Flameblade Adept, Flameblade Angel, Flamekin Bladewhirl
Sword of the Animist although the fact that is being unsheathed sort of ruins it.
Steel of the Godhead, Duelist's Heritage, Blade of Selves, Double Cleave

Duuuuuuude, Radical Jackal you are awesome!
I can tell you put a lot of work into this. Sweet!

Kitsune Dawnblade is epic. Don't care that the sword is curved, it's awesome.
It amazes me that even though I know Markov Blademaster is holding a Trepanation Blade that the red mana flare in the art is overpowering enough that I actually still like it as a "lightsaber."
The two Odric cards have a little more substance to their blade than I normally associate with a lightsaber, but I totally dig the glowy sword aspect.
Vow of Lightning Wow. Just wow. The dissociation of the blade is breaking the immersion for me a little, but I totally see it. I actually think the worst thing is that it doesn't have a handle. Close call for me.
I think the four flame sword cards are pushing it a little much for my tastes. They look more like, well, flame swords than laser swords.
Sword of the Animist still gets a pass in my book. Unless you really focus you can't really tell (or at least it doesn't mentally register in my opinion) that it's being unsheathed. The brilliance of the blade glow just puts everything else into so much shadow that I don't really care. That and the explosion of green leaf particles at the hilt make me think of the starting "snap-hiss" of a lightsaber igniting.

Steel of the Godhead, Duelist's Heritage, and Double Cleave all lose me at having the glow cover the handle too. Duelist's heritage in particular is so close though that I might be willing to give it a pass.
Blade of Selves looks more like a blade of crystal or glass than energy. It certainly glows though.

Nylon.
I caught the Obi-Wan reference right away in Ray of Revelation, but I admit it took me a while to figure out that the Urza's Mine callout was for the little dude in the mine cart looking like Yoda. I was totally sitting here staring at the mouth of the mine trying to figure out who that was supposed to be. XD

Do we just add the 5 sword of X and Y's in here too? Do they count? Most of them have some sort of glowy energy/elemental effect on them, or do they have to be entirely energy based? This looks like a fun deck; dudes with energy swords, wise masters and assorted enchantments/artifacts that are all glowy energy weapons. Does Nahiri, The Lithomancer make the cut as well? Her sword is mostly just molten earth, so it may be outside the remit of this decks intent. Of course, her Stoneforge Mystic persona probably works as a master/weapon forger, so that's on theme.

Rage Forger
Weapon Surge
Deathrender Looks to be mostly physical, not sure if the bladed parts are just glowing metal or what.
Heartseeker
Nightmare Lash Can't tell if made of fire, or simply wreathed in it. Do whips even count?
Worldslayer seems to be similar to Deathrender.
Ghostfire Blade Technically?

Most other equipment is entirely physical as far as I can tell, has a glow that is just light reflecting off it, or has an aura around it, but is still entirely physical. I don't even know where to start with auras and other creatures that might work.

The Odric swords look like the Halo energy swords. I'm less "lightsaber" and more of an "any generic energy blade" kind of guy, so that works for me.

Ghostfire Blade is the strategically best color of lightsaber- invisible. Or I dunno, ultraviolet. I haven't really seen much reference to colors outside the visible spectrum in fantasy media, come to think of it. The Lightbringer books are the only ones I can think of.

Nothing wrong with expanding this list to be generic energy swords I suppose. Makes the four fire blades and the other less ethereal I dismissed before more palatable. Lightsabers may have been the inspiration for this list, but I see no reason it has to stay that restrictive.
Bring on all the suggestions!

Ghostfire blade is Octarine? =p

Hawk, you may be interested to know that in some of the Star Wars books and comics there actually is a lightsaber whip (called a lightwhip). On one occasion Luke had to make a second, shorter, lightsaber for use in his offhand specifically to fight a sith lightwhip wielder.

Searing Spear
Weaponcraft Enthusiast Appears to have some sort of energy dagger/gauntlets
Akroma, Angel of Fury
Angel of Finality maybe.
Razia, Boros Archangel
Lightning Axe
Lightning Javelin
Flame Lash
Geistflame
Doom Blade Sorta, I guess? I mean it's a giant "blade" of doomy black energy. If this counts then so does Arc Blade.
Ghostblade Eidolon Spirity ethereal swords.
Furyblade Vampire Is the same vamp as the Markov Blademaster, again with the Trepanation Blade.
Mistblade Shinobi Maybe? Looks like his weapon is some sort of ropedart thing with blue energy cascading off it.
Thunderblade Charge Looks like she's holding a Soul Reaver in her right hand.

I think that's all I have for now.

Nice work Hawk.

I really like Angel of Finality. I think I'd even put it in the same company as Fiendslayer Paladin and Graceblade Artisan when it comes to the sword looking like a lightsaber (to me anyway).

I'm on the fence about Doom blade only because we can't see the handle. I don't like Arc blade though. It's not even being held, it's just an arc of energy. Not really a sword, though I guess you could call it an energy boomerang. With Doomblade at least we have the benefit of the doubt. We just can't see enough of it to be certain.

Yeah those 2 were the weakest, I was just including them based on their names really.

Martial Glory
Defy Death
Guardian of the Gateless
Furious Resistance if you like your swords to be projectiles
If we are opening it up to non-sword Greenhilt Trainee Temur Battle Rage

Oh, we forgot Nahiri's Wrath, and Lava Axe.

So, throwing together everything we have so far that more of less meets the criteria of "energy/etheral/glowing weapon" and not including the two jedi masters cards that Nylon suggested, I make it to be 53 cards. It's overwhelmingly RW, with only 1 card each in B and G, and with only 2 in U. If you were to make this an edh deck there's no 5 color commander that fits the criteria that I can see. The blue cards are the least nice looking so we could easily drop that color, and as cool looking as they are we could probably just drop both black and green cards too and keep this straight boros, then use Razia as the commander. Dropping black does also mean nightmare lash is less good unless you run an Urborg just to make it do something, so maybe drop that too. That puts us at 48 playables. You could probably just add lands and like, 20 more good cards at this point and this'd be a working deck. Not necessarily a good deck, but a deck all the same.

Martial Glory is preettttyyyyyy! Nice hunting Radical Jackal.

What do you think about Jor Kadeen heading the deck instead of Razia?
He appears to be holding an energy/fire blade as well and mechanically he likes to play with swords.

Huh, so he does. I never even realized that until now. Yeah, you're right, he makes a much better commander for this.

I'm trying to decide if Moonsilver Spear counts. It doesn't glow in this art, but there is a promo art version (that's not on gatherer) here;

where it does, as it does in Avacyn, Angel of Hope, Avacyn, Guardian Angel and the front of Archangel Avacyn. It also seems to be glowing on the statue in Seraph Sanctuary. I guess it's like the Trepanation Blade in that. I'm gona say all these make it in.

I also remembered that a bunch of Gideon art features his glowing surral, like in Gideon's Phalanx, Gideon's Lawkeeper, Gideon's Intervention, the original Gideon's Reproach (is there a way to autocard the specific art on here?), Gideon's Resolve and a few of his planeswalker cards. You're probably not running all of them anyway though.

Some stuff we missed from Dominaria;

Champion of the Flame seems good in this deck.
Fervent Strike
Frenzied Rage
Ghitu Journeymage
Warlord's Fury

These dudes really like flaming weapons.

EDIT; for those still interested, here's the 5 colour pile of everything discussed here http://tappedout.net/mtg-decks/lightsaberdeck-mki/. I haven't added lands, as I'm just using this to list everything that fits the theme in all colours.

The complete 2 colour version is here; http://tappedout.net/mtg-decks/lightsaberdeck-mkii/?cb=1524922960 This is actually a workable deck and doesn't look half bad considering some of the jankier stuff we had to throw in.

Sick deck Hawk. Looks solid.

We should keep an eye on Battlebond because apparently glowing weapons is a large artistic theme for the set.

Yeah I'm keeping an eye on each new set now and adding them to the pile. Eventually I'll make a MK.III 5c version that is actually workable and not terrible. Some of these new red and white cards will probably auto-replace some of the weaker stuff in the boros version, Regna in particular looks pretty solid. Currently I'm seeing at least 10 cards from this set, across multiple colours, to add to the pile, especially in black. Green is still largely under-represented.

We're actually at the point now where it's no longer just about finding cards to fit the theme, but finding GOOD cards to play.

EDIT; Currently we have 86 cards in our 5c list. I found a lot of others through random searching that we'd missed, including Pyre Charger, Archangel of Thune and Paragon of Fierce Defiance. I particularly like that last one.