There are some aspects of logic that aren't required to complete a randomizer seed, but can be useful to know in competitive play.
See the Glitchless Logic and Glitched Logic pages for general overviews of logic.
Important Logic for Weekly Races
Simplified logic knowledge that is useful to know, and targeted towards the settings used for the weekly races: https://docs.google.com/document/d/1hKZYrFhGSGfmrs-wb7004Pn1jpfOBQ4qkcrce51bS44/edit
Water Temple Logic
Water Temple is one of the more open dungeons in the randomizer, as such the logic isn't as intuitive as one may think. ToxicOxygen has created a document describing some of its specific quirks using weekly race settings.
Spirit Temple Logic
Spirit Temple logic is a complicated beast due to how many paths may be taken to proceed. For racers who want to ensure they are understanding the logic the seed is intending for them ToxicOxygen has created a comprehensive document describing the logic when playing with weekly race settings.
The source code on GitHub is the best source for all of the logic in randomizer. Nothing is more complete than the actual logic files used for seed generation. Careful examinations and comprehension of these files will ensure you are never tripped up by logic you come up against in the randomizer.