Murky vs Kel'thuzad
Murky can safely lane against Kel'thuzad. Like Kel'thas his big damage moves are telegraphs and can be avoided. Kelthu'zad excels in team fights so would not expect him to be laning 1v1.
Kelthu'zad has no escape but he will drop his spells at his feet as he is fleeing. You can bubble through these in pursuit but his cool down is shorter than Murky's bubble. So if you don't finish Kelthu'zad off after you first bubble just back off.