Two builds with max synergy?

[Kibou]

The possibilities are a bit overwhelming

I’ll go with melee for now, sword 'n board since that fits soldier and oathkeeper well, and see if I can come up with builds we want to give a try.
Plan B is a pet-based approach.

I’ve been looking for items and devotions that grant bonuses that apply to your ally as well.

Items:
I haven’t had much success searching the database, since there are no filters for this kind of need, and search terms like “granted by item”, “nearby allies” or “meter radius” haven’t worked that well (for example, “meter radius” doesn’t show me Menhir’s Bastion for some reason). What I have so far, I took from the builds linked above: Battlecry (various items) and Menhir’s Bastion from the relic of the same name.

Devotions:
Inspiration from Bard’s Harp applies to allies as well. Does Stone Form from Obelisk of Menhir apply to allies? It has a radius. Assassin’s Mark reduces physical resistance.

[edit]This thread has been extremely helpful:
[1.1.9.1] WyreZ’ Guide to Support Builds: Healing Supports and How To Build Them