Hi! Thank you for showing interest in this old project of mine. Unfortunately there's no way for anyone but me to add brick models. You can only request them in this thread, but as you know, I'm not working on it anymore. However, I'm on the verge of quitting my job, so maybe I will have time soon.
To bad, it's the only good Legobuilding-like game out there :)
I'm sorry to here that about your job, i imagine that it must be tough in this times (Don't have a job, so no idea what's going on :P). Anyway, maybe you could make a Patreon Account or something similar, for those who want to support you. I gladly would :).
Wish ya a nice Day :D