Photon
Shining~
WARNING - SPOILERS FOR HEISEI RIDERS
See above for Wizard. Fourze will lose all his forms in the future. OOO technically only has access to Super TaToBa and no other form (PuToTyra may even be gone forever) but the crossover movies ignore that. Shotaro from W is only able to become Kamen Rider Joker by himself, which happens for a while because plot. Den-O gradually loses the ability to access his Imagin-possessed forms during the show and must "make do" with Liner Form, though later films ignored this (though if Cho Climax is regarded as his final form, he still can't access it without Seig). I suppose technically Kabuto lost access to Hyper form extremely briefly as the original Hyper Zector was destroyed and it took all of one minute for another to arrive from the future. :sweat: And of course Ryuki and Kuuga shouldn't be able to transform at all but all the movies just ignore that.
I meant only the final form, not all the other forms as well, but thanks for the list, it's an interesting read