[LockonStratos]

Well, I feel the obvious idea is for them to be equips. Would probably have some form of protection for the rider alongside an offensive effect to simulate how most Rider Machines tend to act in the shows.

I've been futzing around with this idea for a couple years now, haven't really hit on a concept that I was wholly on-board with. The one that I felt had the most promise was having a three branch archetype based around one of three main "riders," each with a focus on dealing with one of the three major types of cards, so one for monsters, one for spells and one for traps. I'd also recently gotten the idea to split Fusion, Synchro and Xyz along those same lines. Not sure who would get what, although I'm kind of thinking having those be respective could work aesthetically.

Now I'm just spitballing at this point, but maybe having them use your opponent's stuff as part of their upgrades would be a cool concept. Like fusing with your opponents monsters, changing levels based on how many spells they have banished for Synchro plays and using their Traps as Xyz material...