Different strains of kratom of course. Kanna is good if you get quality, I prefer extracts to get desired effects with small dose. Blue Lotus is excellent but very hit or miss on quality. I'm currently looking for a solid supplier. Kava of course. I'm looking into a lecithine/Phosphatidylcholine delivery system for high absorption, experimenting on how to get a good kick from minimal dose. There are some legal cannibinoids as well that have some effect. Betel nuts are cool but kinda nasty and bad for the teeth/gums. Currently experimenting with that.
Ashwagandha helps with kratom tolerance, and will probably offer similar herbs. Will be starting small probably, only offer what I know is effective and high quality so it is a work in progress.