There hasn't been much going on here lately, but I thought I'd throw out what I've been working on for Ekkremes. I know the inspiration for this version of operate came from somewhere on the forum, but I can't remember where.
Tank 4
Artifact Creature
~ can't attack or block unless it's being operated.
Operate 2 (2: Tap an untapped creature you control, you may choose not to untap it during your untap step. It's operating this as long as it's tapped.)
5/5
Goliath 3
Artifact Creature
Reach
~ can't attack or block unless it's being operated.
Operate 1 (1: Tap an untapped creature you control, you may choose not to untap it during your untap step. It's operating this as long as it's tapped.)
2/4
Electric Fence {2/R}{2/R}
Artifact
Operate 1 (1: Tap an untapped creature you control, you may choose not to untap it during your untap step. It's operating this as long as it's tapped.)
Whenever a creature attacks you or a planeswalker you control, if ~ is being operated, it deals 1 damage to that creature.
Machine Operator W
Creature
Artifact creatures ~ is operating get +1/+1
1/1
Smooth Operator U
Creature
Artifacts ~ is operating have hexproof
1/1