To shorten all of my reviews, I'll just mention a couple of overarching things with all of these cards. First, the power/toughness being equal to the number of a certain type of creature on the field is really nice. However, the fact that they all cost 4 is a little expensive. I'd rather see them be 1 colourless and 2 mana of their own colour. Honestly, with the exception of one or two of these cards, these reviews are going to be pretty short (sorry).
Lifelink is great, but "lifelink but not really lifelink" is better since you can stack on lifelink and it will count too.
Trample on a big whump stick? Yes please! Since Elf tribal has gotten a big boost in recent years, this card is one of the strongest in this group.
This is the One that I think doesn't get enough praise. The fact that it has Morph works really well in its favour since it both protects other Morph creatures you have (by giving your opponent another target to swing wildly at) and that it can do a surprising amount of burst damage if your opponent lets it through. Yeah, it doesn't fly or anything, but it's going to be a surprise for sure!
It's a big Goblin with haste. That's about it.
This card can be surprisingly powerful in the right deck. It might not have any evasion, but the fact that it isn't affected by a boardwipe makes it really scary.You could even use Damnation late game and then cast this and you'd have the scariest board bar none.