If you're looking for an aggro deck that's combo-y with fun synergies, you have to try Boros Valor. Arguably the most explosive deck you can make in Duels - you can have draws where you're attacking for 20+ damage on T4. It's very fun to play, and can do a lot of entertaining things.
Version I currently run:
1 x
Kytheon, Hero of Akros2 x
Hanweir Militia Captain2 x
Thalia's Lieutenant2 x
Selfless Spirit2 x
Kari Zev, Skyship Raider4 x
Aether Chaser3 x
Honored Crop-Captain3 x
Harnessed Lightning1 x
Declaration in Stone2 x
Pia Nalaar2 x
Hanweir Garrison3 x
Thopter Engineer2 x
Pia and Kiran Nalaar3 x
Valor in Alros2 x
Sram's Expertise1 x
Gideon, Ally of Zendikar1 x
Angel of Invention7 x
Plains7 x
Mountain2 x
Needle Spires2 x
Westvale Abbey2 x
Clifftop Retreat1 x
Hanweir Battlements3 x
Aether HubMana base is pretty greedy, but I'm ok trading a game here and there where I mulligan a string of Hub/Battlements/Abbey hands to death for those games here and there where I flip Abbey or transform a Garrison FTW. If you prefer consistency, trade in some of the R/W tap lands to help you hit your T4 double color spells on curve (only a single 1 drop makes it no problem to spend T1 playing a tapped land). I wouldn't go above 24 lands cause flooding out with this deck is the worst.
I've run versions with Smuggler's Copter for the loot effect to power through floods, and that's a viable option to sub in too (just remember to pilot it before your Valor triggers resolve so you can get dem big Copter swings). Another vehicle I've run at times is Aethersphere Harvester - more energy plays well with Hubs, Lightning, and Chasers - lifegain is useful at times, and it's a big butt on defense. Current version doesn't use any vehicles cause I got bored with using them in decks - this version is more focused on aggressive synergy and T4/5 wins.
Thalia's Lieutenant, Crop-Captain, and Gideon Emblems help you pump weenies to win games you don't draw Valor in. Abbey helps you win stalled games you can't find/stick pumpers in, and I'd run a single copy even in decks I'm subbing R/W tap lands in for better color consistency. Battlements is primarily a just for fun card - occasionally you'll use the haste option to send in a creature who just valor pumped your team for a bigger swing, and every so often you'll be able to transform Garrison for a super fun swing. Mostly it's just a colorless land source tho, that's as likely to frustrate you by not producing a color as it is to entertain you with its abilities. But I run a single copy for those rare occasion where it does something cool and makes you feel good.
Another deck I keep coming back to because it's combo funtastic is Fling-A-Drake. You can find builds here:
https://www.nogoblinsallowed.com/viewtopic.php?f=61&t=18840&start=0It's not aggro at all, but is a blast to play. You spend most of the game aggressively decking yourself and defensively fogging/TITI bouncing/sweeping to stay alive, then suddenly dropping a Drake and flinging it for an instant kill. It's relatively common to get opponents pause spamming at lethal cause they can't believe they spent the whole game feeling in control and on path to victory and you just flung 20 points of damage at their face out of nowhere.
(This list from Giocher is the version I like best on the random ladder, with 2x
Commencement of Festivities in place of 1x Baral and 1x Dispel:
https://www.nogoblinsallowed.com/viewtopic.php?f=61&t=18840&start=0#p563863)