If you want to block tracking scripts, Ghostery is the go-to extension for that.
A lot of them, yes. But there are techniques like browser profiling or persistent cookies[1] that still manage to trump a lot of them.
The best blocker I've come across is ublock, amazingly memory efficient, fully customizable and featuring so many good block lists that it should block at least as much as ghostery or disconnect (if not more). Just the GUI looks a bit .. functional