An extremely simple yet potent checkpoint merge I've been using:

66.7% Matrix-Hentai-Pony-v1.6.0b
33.3% T-ponynai3-v5.1

and a basic sdxl vae to get it to work in fp16 so it doesn't black screen without the --no-half and --no-half-vae arguments.
Great out of the box, and plays nice with long complex prompts and multiple LoRAs. Vaes are baked in from both sources and from myself, so none are needed. I like to run it at 15 step per 1024x1024 image with cfg at 3.5

WORKS BEST WITH HAKO-MIKAN'S PREVENT ARTIFACT EXTENSION!!! Honestly if you're using pony you should use it regardless, as it completely nullifies those junk generations you get all too often of just color blobs. I'm genuinely surprised it's not on the official extension list at this point, you still have to download it via the url tab.

I put most of the LoRAs I used in the examples in the suggested section fyi.