Artifacts that produce slow or expensive value, or can be combatted by an opposing welder, or that can't be cheated in by welder are allowed to be more powerful. Examples include Planar Bridge, Arcbound Overseer, Legacy Weapon
As many cards as possible should be useful for multiple themes
For the challenge in design, and for the simplicity of the ruleset, no added rules like "Welders can't die"
Welders should generally stick around, so stay away from removal and sweepers that hit them (looking at you, Pithing Needle and Pith Driller)
ThemesTribes & Changelings ()Changelings abound!
As do ways to use them!
5-colorGet to 5 colors
Look for payoffs in
Populating the graveyard ()Putting artifacts in your graveyard gives more options for your Welder
Purging the graveyard ()Manipulating the cards in your own graveyard can take choices away from your opponent's Welder
Ramp ()Hit big payoffs
Cheat into play ()Bypass the ramp and cut to the chase
Bogles ()Ways to pump that matter even with Welders around
And creatures to amplify them
Artifact combat ()Flood the board with artifacts and put the pressure on
Stompy ()Play oversized and hard-hitting creatures
Mill ()Deck your opponent
Or mill yourself
Tap-down ()Tap down big creatures or gain Welder tempo
Get hell-bent ()Empty your hand quickly
Aside from putting the pressure on fast, look for these rewards
Burn ()
Untap ()Ramp, combat utility, more Welder activations
Germs ()Living weapons come and go and move around