Swain Support is totally underrated
Yesterday I hit Master for the third time in my league career. While the first two times it was mostly Bard, Seraphine and Renata I decided I want to try my best with one of my niche picks - Swain. Now I stand with around 200 games on Swain with a 59% winrate.
The amount of pressure in lane is great, the w is netting assists or cut off ways to escape and lure enemies into unfavorable paths. Most of my games I end with around 700-1000 bonus hp through passive.
Build is nearly always the same. Get Rylais, boots, liandries into zhonyas. Mix in some anti heal if necessary. If their mainsource is ad go for thornmail. If its mixed or mainly ap go for oblivion orb. If somebody else builds it I am happy for another tank item on last slot.
Swain pairs incredibly well with cc providers. Jhin, Ashe, Caitlyn, Seraphine. Senna is also good but sometimes too weak early to utilise swain kill pressure.