I'm looking for the least amount of stretch, close to braid in 15-20 lb test.

No nylon based line is going to be even close to braid as far as the stretch is concerned.

According to FryDog's tests, copoly would be your best bet. The tests were done dry, but yozuri hybrid would be a good suggestion seeing as how it doesn't take on water.

fluorocarbon lines loses much of its stretch if you stretch it hard once, but as a whole, nothing comes close to braid as far as long distance hooksets are concerned. If its close range, less than 20-30 feet, it doesnt matter too much.

Lowest stretch non-braid is sunline shooter. It's tough as nails when it's wet.

Spiderwire Ultra Cast Ultimate Mono, it is being touted right now as the mono with the least amount of stretch. I'm using it in 6lb and 8lb for spinning and 14lb for casting and so far it really is low stretch, my buddy is using Seaguar Red Label and with my rod he said his line feels like it has more stretch than the Ultimate Mono I'm using. It isn't close to braid but it is the lowest stretch line I ever used and yes, I have used fluorocarbon line before. The one problem with the super low stretch is memory, on the casting rod it isn't bad and it says on the label that it is optimized for casting reels, however with a couple of spritzes of KVD Line and lure it becomes very manageable, it does act like fluorocarbon but not as extreme as the memory is more than I like but it isn't that bad that it becomes a problem.

Lowest stretch non-braid is sunline shooter. It's tough as nails when it's wet.

this.

P-line cxx is what you're looking for.

P-line cxx is what you're looking for.

Just ordered a spool of 20 lb for swimbaits. How is the abrasion resistance and knot strength compared to some fluorocarbons?

Jiggin- Amazing for both.  You will not believe how strong and tough this line is.  My only advice is to use some KVD L&L to tame it down a bit, as it does have some serious memory.

P-line cxx is what you're looking for.

 

Agree, I use 10lb all the time. Long cast, low stretch, good knot strength and abraision.   no hook up problems.   It isnt for spinning reels unless you go lighter.  I do use 4lb for spybaits on a spinning and it really cast out there.  

Just ordered a spool of 20 lb for swimbaits. How is the abrasion resistance and knot strength compared to some fluorocarbons?

My #1 line. It has probably the least stretch of any line I have ever really used other then braid. Not to mention.the amazing sensitivity and toughness.