Here's another good hack for Wily Wars called Classic Fluency: http://acmlm.kafuka.org/board/thread.php?id=8962
My current setup is this, Flow, weapon refill, and Wily Tower always available. It's good stuff.
Some other stuff...
The Dynamite Headdy retranslation is good stuff: https://www.romhacking.net/translations/1113/
So is Panorama Cotton: https://www.romhacking.net/translations/4292/
Shadow Dancer has a patch that adds 3 HP like Contra Hard Corps, but I won't link it here because all I can find is a pre-patched ROM.
The Phantasy Star 2 Improvement makes the game more fun and approachable, there's an XP and cash doubler inside the zip too: https://www.romhacking.net/hacks/925/
The Sonic 1 "Bugfix" actually adds the Spindash as well, makes a world of difference and the palettes look good too: https://www.romhacking.net/hacks/4956/
Sonic 2 Anniversary Edition is good too, a nice companion in between the Sonic 1 Bugfix and Sonic 3 complete. Again, not linking it because it's found in pre-patched ROM form. Sonic 2 Bugfixes and Knuckles has a lot of the same stuff, though it's missing the new graphics and Hidden Palace Zone. Tails can carry Sonic though, so it's better for co-op: https://www.romhacking.net/hacks/4957/
For the Master System...
The Phantasy Star Retranslation is at the top of the list: https://www.smspower.org/Translations/PhantasyStar-SMS-EN
. I prefer the old-name version for 2.01. Add the sprite hack and it's a SNES-caliber RPG: https://www.romhacking.net/hacks/5248/
Sonic Triple Trouble GG2SMS: https://www.smspower.org/Games/SonicTripleTrouble-GG
Tails' Adventures GG2SMS: https://www.smspower.org/Games/TailsAdventures-GG
The Golden Axe Genesis port makes the SMS port largely irrelevant, but this Tyris Flare hack looks a lot better than vanilla: https://www.smspower.org/Hacks/GoldenAxe-SMS-TyrisFlareEdition-Mod
Ecco 2 Rev. 1 is a solid improvement over the Game Gear and Brazilian releases. Fun fact: the Genesis, 8-bit, and Sega CD versions of the Ecco series all have completely different soundtracks! https://eccothedolphin.online/ecco-2-revision-1-master-system/
Zillion's text fix is a nice bit of polish: https://www.romhacking.net/hacks/879/
Also lots and lots of Alex Kidd hacks on SMS Power.
The Genesis has been getting more love with hacks lately, so it's a good idea to pick a game that sounds interesting and see if there's any hacks for it in the database. There are more hacks for the more popular games, this is just the stuff I've played.
Also, Jorpho, that last link you posted was for SNES hacks... not that I'm complaining about SNESDrunk videos though =P