People can see the cards i've rented here:
https://peakmonsters.com/@archmagebot/

But that is a good suggestion. I will try to find those cards that I didn't even use once. To start the bot, I just rented some water cards to start with and some dragons and neutrals as well. Not a very good variety.
Llama + kron is a good combo but it has to fit in the mana/ruleset and is kinda expensive compared to what I spent.