Well lets not forget that custom races are also allowed, and they could easily keep up with Sayans. Plus Majin/androids could also probably keep up pretty well. And the reason Sayans are so strong is because Toryiama is a horrible writer past Dragon Ball. Pretty sure we can all agree on that bit, otherwise it wouldn't just be Goku/Vageta, one of these characters only going for the kill steal and having 0 character development all over Z.

Or just get a vial of Beerus's blood and do stuff with that. He sleeps like a log so he wont notice a small needle covered in painkillers. You just need to bribe Whis, or get his blood, but meh.

[hider=And Goku is a Wimp]And ofc Goku gets beat by a tiny laser beam when hes SSGSS, so... yeah.[/hider]

Or just use nanobots/poison. Majin/Namekians/demons/custom race could prob survive that, but not sayans.

Or Magic. Babidi was easily the strongest char in the buu saga if he had any brains.