Hey @alberto - welcome to the forum my friend! So glad you have joined us, and thanks for making the great point here.
And @LostSol just posted an awesome channel that has tons of tongue blocking on it.
If people know other awesome tongue-blocking YouTube channels it’d be great to share them here or on that thread. 
Also @David312 IN MY OPINION if you can try to start working from memory rather than relying tabs, I find it to be a much richer experience. I would rather work on 4 notes of a song from memory, than a whole song by tabs. I find I just can’t “become one” with a song, if you will, when I’m trying to read tabs.
That’s my 2 cents.