I need some help with a Card/Unit

Would be happy to provide some help, the crawling units you mention can either be the Nod Cyborg if it causes an electric shock effect when hitting a vehicle or it can be the GDI Zone Trooper which actually uses a railgun and has a big armored suit. Whether it is the GDI Zone Trooper or Nod Cyborg both units can be countered by GDI Rifleman/Nod Militants, GDI Wolverine, Nod Flame Troopers, and Nod Flame Tank.

The Hover tank which is the GDI Sandstorm is a late game anti vehicle and anti air, the best to deal with it are GDI Rocket Squads/Nod Laser Soldiers, your GDI Sandstorms can counter them if the get the first rocket barrage off in the case they are set up on the launch control platforms. If not then two squads of GDI Rocket or Nod Laser Soldiers will do wonders against them as GDI Sandstorms cannot do much damage to them while they take a lot of damage in return from those anti vehicle infantry. Do not send GDI Predator Tanks,  Nod Attack Bikes or Nod Scorpion Tanks against them as the GDI Sandstorm is very effective against these units and will kill them in one rocket barrage. Another unit that is a decent counter if you have it are GDI Titans (big walker mechs with a railgun) or Nod Cyborgs because they use an anti vehicle particle beam that slows down any vehicle along with their attacking speed.

When it comes to the Nod Rockworm, it currently is a problem as the only real good counter to is anti vehicle aircraft like the GDI Orca or Nod Banshee but again GDI Rocket Squads/Nod Laser Soldiers do decently well against it, along with GDI Zone Troopers or Nod Cyborgs. But do not send out GDI Sandstorms against the Rockworm as the Nod Rockworm is a heavy anti vehicle unit and will absolutely destroy anything that is a vehicle.

I hope my advice and suggestions helped, best of luck in your future battles.