@Nanonox was right,
Hardened Academic has been a great addition!
It's not a card that you build around or that creates a new archetype, but it has increased deckbuilding variety just by existing. It's a support card for several, overlapping archetypes so you often take it for one theme and end up it for a second one:
- Haste 2/1 flyer.
- Lifelink
- Discard outlet
- +1/+1 counters
It's not life-changing, but I have seen an uptick in Boros discard decks the moment I added it. Phlage, Titan of Fire's Fury is already a good card and they work well together in midrange, heavy discard and even controll-ish shells.
It's a shame there are not many black or red creates with +1/+1 counters, if there were any, I think there would be more crossover with white.
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I run one too many black graveyard creatures, particularly after the addition of
Darklight Phoenix. Gravecrawler is staying so that leaves me with:
Bloodsoaked Champion helps bridge sacrifice and humans. WB Aggro is less common lately than I would hope, though.
Bloodghast is, theorically, playable in any deck and can be abused by bringing it back several times a turn. However, I don't see that too often and the 2/1 body makes me a bit unhappy. Perhaps I should pair it with more equipment, not just expect to go in with nothing.
Scrapheap Scrounger should be worse than it is, but I like its natural 3/2 body. It's big enough to not be blocked freely and it's scary with equipment. Still, I suspect it's one of the most likely cuts. I might like it better than Bloodghast but, objectively, I don't know if I would choose it over its landfall friend.
Prized Amalgam is good and promotes graveyard decks, but I feel I might already have too many "free" creatures that wheel to this deck, as I have Vengevine, Darklight Phoenix, Anger, Blazing Rootwalla and Basking Rootwalla. It ends up being a free pick and an autoinclude. I could cut it or a rootwalla and not lose too much.
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I put these on my cube and I like the cards but I've yet to build a good deck with them:

There are a couple problems with this build. The first is that, if you use these, you need to win that turn. That means storm, which means Tendrils of Agony or maaaaybe Chatterstorm and Awaken the Woods. Even if you stretch into other colours, that's not a lot of ways to win and you often lack any.
The deck is fragile because it relies on a bunch of 1-ofs like those two cards, Fastbond or Yawghmoth's Will. It doesn't benefit much from Lion's Eye Diamond or Dark Ritual, either, and it often needs to splash for key cards. Green is also lacking in defensive options for combo. Life loss is an issue, both Fastbond and Ominous Harvest can kill you quite fast. Ultimately, the deck looks like it could work but that it will fall apart.
Ultimately, if Squandered Resources also let you sacrifice creatures...then we would talk. But like this, it's tough.