When I was doing Ironmans these workout flash cards were clutch. They’re organized by time and focus area (endurance, strength, distance, speedetc.) and they have some equipment options (paddles, flippers, board)
Buy this book
I found a great book on Amazon, I've been really enjoying the workouts (and the pages are waterproof!)
Workouts in a Binder for... https://www.amazon.com/dp/1931382743
This book has a bunch of different workouts: