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I don't think I have enough cartoons in mind that I really liked for a list of ten, let alone actually rank them, so I'll just list the ones that quickly come to mind.
Perhaps it's no secret by now that My Little Pony: Friendship is Magic would be on my list, as well as the spin-off series Equestria Girls (which I actually like more than the main pony series in some ways). I also really liked the G5 MLP series Make Your Mark (less so the complimentary series Tell Your Tale, but it's had some good episodes).
If Bionicle ever had a TV series, it would've absolutely topped my top ten list, but alas no such thing exists. However, I did watch the first ten seasons of Ninjago: Masters of Spinjistu (I hope to eventually watch the later seasons as well), and while I wouldn't call it a favorite, it was good enough to get me interested in some other Lego shows that I would like to watch at some point (Lego City Adventures is one that I'd especially like to get around to seeing relatively soon).
As some of my early post history on this site can attest, I used to like Total Drama during its first three seasons. I chose to stop following it prior to the fourth season (news of extensive editing following the 2011 nuclear disaster in Japan made me concerned that season's quality would suffer as a result), and while I still have no desire to see where that show has since ended up, it certainly had enough of an impact that I'll always remember it.
While I watched many cartoons as a child (as any other child would), the one that definitely defined my later childhood was Ed, Edd, n' Eddy. These days, I'm not sure if I could bring myself to actually watch it again, but back when it was on the air, I had absolutely loved it. Aside from the Land Before Time movies, it was one of the very first shows I had ever gotten truly obsessed with watching all the time, so it will forever be part of my childhood nostalgia.