I love love love Seeker of the Way, Monastery Swiftspear is fine, I want Jeskai Elder to be good but I'd rather have another Looter il-Kor. The new prowess guys all look awesome - for Mentor the question isn't whether it's good enough, it's why there are so many good white 3-drops.
Obviously Auras are nice with these as detailed in the Auras Equipment thread, but so is Equipment! Grafted Wargear is excellent just like it is elsewhere, and this might be enough to make Bonesplitter good too. I like Runechanter's Pike.
You also want:
- Non-creature spells that generate threats: Hordeling Outburst/Raise the Alarm/Spectral Procession/Lingering Souls/Battle Screech/Call of the Herd, Bitterblossom, planeswalkers, bestow (Gnarled Scarhide, Hopeful Eidolon, the mighty Nyxborn Rollicker, Mogis's Warhound, Spiteful Returned, Boon Satyr, Eidolon of Countless Battles, Herald of Torment, Nighthowler)
- Multiple triggers from one card: rebound (the cards you mentioned + Consuming Vapors), flashback (Souls/Screech/Call, Thrill of the Hunt/Travel Preparations, Faithless Looting, Firebolt, Blast from the Past), Regrowth
- Repeatable triggers: dredge (Darkblast, Life from the Loam, Moldervine Cloak), Grove + Punishing Fire,
Whiteout (maybe not...), buyback (
Haze of R Sprout Swarm, Blast from the Past)