I currently use the Lancôme art liner which is really good and easy to use but I think it's like £23 so that's something to consider. Staying power 9/10, application 8/10.
Maybelline gel is really, really good, great staying power, comes with a wand to use so that's handy. Think it's £7/ £8. Staying power 8/10, application 9/10.
17 Tattoo Me- the best staying power I've ever seen in an eyeliner but a bit fiddly to apply. I think it's £4- the staying power would last through a war. Staying power 1000000/10, application 6/10.
Benefit Push Up- good at first but dries so quickly. Application is fine, nothing to rave about. Staying power a bit meh. 6.5/10 for staying power, 7/10 for application.
Kat Von D. Amazing stuff. 9/10 for application, 9/10 for staying power.
Rimmel glam eyes. Good for price, not as good as high end IMO. Application 7/10, staying power 6/10.
Soap and Glory cat eye. Application is good but pigment isn't the best. Staying power is okay. Application 8.5/10, staying power 7/10.
All opinions are my own. If I think of more, I'll add 