So something looking like a Graze from Iron-Blooded Orphans would work perfectly as a design to base our mechs on (The mobile suites in that series don't use energy weapons at all, although its mainly because that technology was long lost in that shows past).
However I'm sure there are other...
*Kicks door open*
Gundam and Muv-Luv Inspired?! Count me in!
(I also am familiar with Evangelion but you drew me with Gundam and Muv-Luv)
What do you want our mecha to look like in this rp, so we can have a kind of unifying appearance
Alternatively, if they had a very specific weapon attributed to them, use that instead as your NP.
As an Example (using one of my submitted characters)
Lyn possesses both the Sol Katti and Mani Katti. The two swords are ancient weapons that can only be wielded by the one they deem worthy. The...
We have a Catgirl archer named Atalanta. I think its fine as long as its not too animalistic. Also make sure to nerf its godly feats because we don't do EX ranks here