There are 7 basic knots taught in Scouting
Square Knot
Bowline
Sheetbend (not sheepshank)
Clove hitch
Two half hitches (aka double half hitch)
Tautline hitch
Timber hitch

Of these, I use the bowline, tautline and clove hitch the most.
Tautline is on my guylines
Clove hitch at the stakes
Bowline is handy for all kinds of things.

I also use Prussik knots in short loops on my ridgeline to attach my tarp.
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If you think you can, you can. If you think you can't, you can't. Either way, you're right.