The only one I have is Blue Raspberry Slush. It's really good at 12-15% standalone. It doesn't need much of anything added to it. Maybe either 1% EM, .5% INW Raspberry, or I dig .5% FA Lemon Sicily sometimes. Don't forget it's VG based, so make sure you change that in your calculator if you're mixing by weight.
Ok...I disagree...blue raspberry slush works way better w some kind of a blender or smoother flavor like marshmallow @ 4 to 6% some sweet cream and I mix vanilla swirl n yellow cake in that...their Arnold Palmer is good but try adding raspberry vanilla and you'll get a lemon raspberry tea that's incredible...not liking that they put "high fructose corn syrup" in that Lucky Shot but I use this as a base for my caramels...Kimberly says adding key lime creates that key lime pie...I'd say the 10 to 15 percent range works best...
I will say Slush is probably my favorite standalone flavor, but I agree it's better w/ added flavor notes. My preferred addition has been tfa sour at .5% as of late. Sweet cream is another good one, but I've found I prefer tfa sweet raspberry to slush when mixing with sweet cream.
My standard slush mix is 18% w/ .5% tfa sour max VG. Seems a little high, but is needed when you're not using any PG besides the sour imo. 8% tfa sweet raspberry + 4% sweet cream is the other mix I mentioned. These are two of my favorite shake n vape/shit I ran outta juice/I'm too lazy to mix anything interesting recipes lol.