The Ultimate - and I mean ULTIMATE - guide to ritual spellcasting in 5e. The author even used color-coding. This is awesome.
For example, it seems so obvious to me that a ritual casting would require the character to stand still, but apparently not. The character can walk and chant at the same time.
The color-coding is great, and makes it really clear the only spell list worth ritualizing is the wizard spell list. Well, that is unless or until we get a 5e version of "Relics & Rituals" which expanded the ranger and paladin lists so incredibly much that we actually had someone play a ranger with Scribe Scroll, just so she could use all those cool spells (and wow, did she).