Awesome

wyrde-comfyui-workflows

some wyrde workflows for comfyUI

basics: some low-scale workflows. Good ways to start out. Beginning tutorials.
compare workflows that compare thintgs
funs workflows just for fun.
hr-fix-upscale: workflows utilizing Hi-Res Fixes and Upscales.
misc: various odds and ends.
others: workflows made by other people I particularly like. Or had the urge to fiddle with.
templates some handy templates for comfyui
why-oh-why when workflows meet dwarf fortress

The custom nodes and extensions I know about.

Many custom nodes are provided as packages on civitai.
Use the "other" type in filters or search with the comfyui tag. <img src="https://user-images.githubusercontent.com/9657443/232229734-e1e662f5-d534-413d-9a05-24a09abfef20.png" width="20%" align="middle">

Upscale Database
- note: stick to the universals unless there's one that fits specific needs
- I often use 2xPNSR for quick upscales (first line, in source section).
- lollypop x4 is my favorite for illustration style images.
Upscales at HF is an archive of some upscalers on huggingface.
A handy chart of aspect ratios from a reddit post
MisterRuffian's Latent Artist & Modifier Encyclopedia
Pickel Scanner
Stable Diffusion Prompt Reader

XNView a great, light-weight and impressively capable file viewer. It shows the workflow stored in the exif data (View→Panels→Information). Also has favorite folders to make moving and sortintg images from ./output easier. There may be something better out there for this, but I've not found it.
Powertoys make windows experience more pleasant. Especially windows terminal
process explorer get a better look at what is going on. Add the "GPU Dedicated Bytes" column and see what is eating away VRAM