Engage tank rune set up! (Supp+Jgl)

If you're an engage tank a really good set up is: Aftershock, Font of Life, Conditioning, Unflinching + Triumph, Legend: Tenacity

Triumph heals for 12% of your missing hp, and if you're a 5k max hp on 1k hp, you get 480hp back for an assist (and 150+20g), the person doing the killing gets healed from font of life (would be 55hp over 2 seconds here, but it'll just add to the pile of ambient healing they get)

You get resists from Aftershock and Conditioning

You don't become a useless blob of hp by getting CC'd, you have 30% max from Legend: Tenacity and a max of 32% from Unflinching, if you also get Merc treads for another 30%, you can achieve 70.25% CC reduction. Tenacity stacks very weirdly, to put it as basic as I can it's:

1-((1-passive tenacity)×(1-item tenacity)×(1-Tenacity obtained from activated abilities/spells )×(1-0.65 ))=CC reduction

in this case I think that means

1-((1-(0.2+0.3))×(1-0.3)×(1-0.15))~~0.7.

~70% is really good in a fight, albeit you'd need to have spent both summoners to get this, but you often use them in the engage anyway. More tenacity means you can get more CC off and possibly receive more enemy abilities

This isn't so good on tank toplaners because aftershock isn't really a good toplane rune for a tank, this is more for engage supports and junglers