My son has gotten into knex recently, and likes making robots out of them... So I figured I'd stoke/seed his creativity a bit by making custom knex pieces that have robot kitbash components on them (random panels/weapons/etc)
This is an example of the type of kitbashes I used:
I took the knex set here: https://www.printables.com/model/143840-knex-parts-customizable and added some of the kitbash pieces to male/female connectors.
And here is an example of something my son made tonight: