After reading 5-6 pages of this, I found that not many posts identify "Large purchase credit card bonuses", so I created a wiki.
If you all could add to the list that would be great. I don't use hotel cards, but if someone wants to add a section for that, please do so.
My scenario - Due to my home airport (Jackson Hole) being so expensive, I can routinely redeem United points in economy for 3-4 cents per point. Trying to figure out my best options for putting $20-$25k/month of business expenses through Plastiq. My best options right now are United Club card - essentially buying points at around 1.5 cents. I'm trying to find other options. I know this isn't good MS Spend, but it's setting it up automatically and doing it from your pajamas easy. Cashback cards in my case don't make sense.