ennki's Kamen Rider Decade just because you can transform into any of the first 9 Heisei Main Kamen Riders and use the K-Touch to transform into his Complete Form
I no Soko no Rikugame's Megaman/Rockman.exe due to him having the battle chip system and custom gauge from the Battle Network/EXE games
darknesskyo's Star Force Megaman/Ryuusei no Rockman due to him taking a few cues from the actual Star Force/Ryuusei no Rockman games while still playing like I no Soko no Rikugame's Megaman/Rockman.exe
Amada's Freedom Gundam -METEOR- can hop into the METEOR Unit and wreck some havoc on your foes
Team Gaim's Kamen Rider Gaim due to him being able to fill up his special gauge and transform into major lockseeds from the show
BlackCat's Kamen Rider Kuuga because he can turn into all of his forms and has a one-hit KO where he turns into his Ultimate form
Jaki's Kamen Rider Blade because he can transform into his King Form and use all of his rouze cards
ev133's update of Alf's Kamen Rider Kabuto because he can use Clock-Up, Cast Off, his Kabuto Kunai Gun, and transform into Hyper Kabuto