Swain + tahm kench botlane
Me and my mate plays this combo alot in botlane (we are plat/emerald).
I wanted to recommend it, since its a very fun combo. We can usually brute force our way through the lane and win most encounters!
Swain takes the farm, tahm supports. It works the other way around as well but easier for swain to farm.
The setup pre 6 is either:
Tahm q - swain e - tahm w - swain w + q. This is usually enough for a kill or atleast forcing a recall.
The real interraction is that swain R stays active if tahm eats him. So swain can ult and tahm can eat him and tank for a bit to let swain keep R up for a longer time, kind of like a free/moving zonyas. This is crazy good for teamfight, especially with rylais on swain.
Have fun!
Bonus forbidden tech: swain supp + sion adc. Their setup with sion E into swain combo just feels great, and swain E into fully charged sion q hits like a nuke!