A sheet bend and bowline knot are both wildly useful. But a bowline is just a single rope sheet-bent (sheet bended?) back onto itself! And a trucker's hitch is just a slip knot where you creatively use the slipped loop as a pulley.
And a highwayman's hitch, just for fun
A reef bend also works, but has many ways to tie it wrong.
The most important thing is to know when to use what.
I would recommend looking at the ones that are thought in the Irata and Sprat certifications. IIRC there is fewer than 10 but there is a wide range of ways you can use them or combine them together.
Taut-line hitch
Sliding knot for fastening loads or setting guy-lines https://www.netknots.com/rope_knots/tautline-hitch
Bowline
Essential general knot for tying a loop. https://www.netknots.com/rope_knots/bowline
Square Knot
Used for joining ropes or just an easy to unite knot. For joining ropes you could do a sheet bend which is stronger https://www.netknots.com/rope_knots/square-knot
https://www.netknots.com/rope_knots/sheet-bend
There are a billion options so I recommend just picking a few and practicing until you can tie them quickly without references. You'll start to understand hope knots in general work and be able to pick up other knots much easier.
If you care about safety, look for knots used in climbing instead.
Beware the truckers hitch, it is not a real knot so should be secured by one. But super handy for making a line nice and tight. The one I picked up is this over complicated version that has the nice property that it is in-line, that is, you don't need the far end of the rope for it to work.
My personal short list are the following:
1. Joining two ropes (i.e. bend): Zeppelin bend, or Figure-8 bend. If the ropes have a very different diameter you will need a different knot, such as a Double Sheet Bend.
2. Holding on to an object (i.e. hitch): Two Round Turns & Two Half Hitches. More turns and half hitches make it more secure.
3. Making a fixed-diameter loop at the end of a rope: Figure-8 loop.
4. Making a fixed diameter loop in the middle of a rope: Alpine Butterfly, or simply take another piece of rope and do a Prusik Loop.
5. Grabbing onto a rope, such as when you want a loop that can be cinched down (i.e. friction hitch): Icicle Hitch. I personally do Round Turns & Half Hitches instead, and will die on that hill.
Another useful trick that can be done with a combination of the above is called a Trucker's Hitch. It is not so much a unique knot, but a common combination of the principles above.
For those who know about knots: please resist the temptation to nitpick and offer alternatives. Yes, there are many others. No, it doesn't matter. The knots above, or a combination thereof, covers 95% of everything you can do with rope, they are safe, and easy to verify.
I see a lot of posts here along these lines. It turns out there is a trade-off between knots: how easy they are to undo vs how likely they are to spontaneously untie, particularly when not under load.
Most of the "every knot you need" recommendations here seem to come from people tying things down for a short haul, and consequently come from the the "easy to untie" end of the spectrum. The sheepshank is great for a temporary tie down but obviously falls apart when not under load. Less obviously so does the bowline, figure 8, and most knots composed of half-hitches.
A rock climber takes a dim view of knots that spontaneously untie when they aren't looking, so they use a different set of knots. At the extreme are fishermen. A single strand of nylon is slippery, is weakened by kinks, and yet a fisherman's knot must remain secure while drifting in the surf being bashed waves. Consequently, they will use complex, slow to tie knots with 7 or 10 loops.
Your knots look to be at the "easy to untie" kind, except the alpine butterfly. If it has been under high load for a while it can be a real bitch to get apart. It's popular with climbers, but I would not recommend it for tying down a load.
Agreed. There are many tradeoffs, indeed. But just because there are ten common knots that can do a bend, it doesn't mean that a person benefits from using all of them -- they all perform the same function, so knowing a single secure bend is enough, especially for a beginner asking these sorts of questions.
Personally, I have chosen my knots based on how safe and effective they are, as well as how easy they are to remember, tie, dress, verify and untie after load. The Zeppelin bend is hard to verify against e.g. the hunter's bend or Ashley's -- but it's just as secure as a flemish bend at a fraction of the effort to tie. The double sheet bend is bleh, but I didn't want to get into the weeds of what to do when joining ropes of very dissimilar diameters.
> Most of the "every knot you need" recommendations here seem to come from people tying things down for a short haul, and consequently come from the the "easy to untie" end of the spectrum
Agreed. I would say camping-style knots tend to be easy to tie, easy to untie, and not adequate for safety critical applications.
> Your knots look to be at the "easy to untie" kind
If you mean "easy to untie after being heavily loaded", then we agree. If you mean "can become untied accidentally after e.g. intermittent loads", we disagree. They are climbing knots, after all.
I specifically did not include knots that are commonly recommended even though they untie easily e.g. under intermittent loads, such as the sheet bend or the bowline, precisely because of how easily they become untied.
> It's popular with climbers, but I would not recommend it for tying down a load.
I am not in love with the alpine butterfly variations in general, but in the specific context of making a midline fixed loop without access to either end, there's not much to choose from as far as I know. The Figure-8 capsizes in that application, for example. That said, I would rather use an accessory line with a friction hitch (e.g. Prusik loop), but an alpine butterfly is commonly used in safety critical applications as you mention, so I'm curious to learn what you would rather use in that situation.
As for fishermen and safety, how do you explain that they still commonly use the bowline or the sheet bend?
I've not seen a lot of fisherman use them myself. But if they are indeed common as you say, then it must mean most fisherman are beginners.
Fisherman are nice people. They help each other out, and they learn fast. For example when a fish falls off the line a beginner will often loudly proclaim it bit through the line. Someone with experience often takes that opportunity to look for the telltale curls in the nylon line indicating the knot had slipped, rather than being cut. If they see them, they will often congratulate the beginner on nearly catching the biggest fish of the day - it's a shame they don't know how to tie a fishing knot.
> I specifically did not include knots that are commonly recommended even though they untie easily e.g. under intermittent loads, such as the sheet bend or the bowline,
Ahh, sorry. Reading comprehension fail on my part. I confused your post with others that mentioned the bowline. It's a wonderful knot, but it must be kept under tension.
> alpine butterfly is commonly used in safety critical applications as you mention, so I'm curious to learn what you would rather use in that situation.
As I said as the start, I was thinking you were recommending knots for casual use. I'd use the Alpine Butterfly when I want something that won't slip in that situation, however I quietly curse under my breath while tying it because if it gets tight I've created a lot of work, particularly if I don't have a marlin spike handy. I haven't owned one for years now, so I go out of my way to not use the butterfly.
I gave some quick guidance for newbies with some broader context to help them, only to have somebody dismiss everything I said because they didn't pay any attention to what was written.
Next time, please do read what you reply to, especially if you are going to be dismissive. What a waste of everybody's time. I was hoping to learn something new. Bleh.