Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

Mazemind Tome

{T}, Put a page counter on this artifact: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{2}, {T}, Put a page counter on this artifact: Draw a card.
When there are four or more page counters on this artifact, exile it. If you do, you gain 4 life.

Servo Schematic

When Servo Schematic enters or is put into a graveyard from the battlefield, create a 1/1 colorless Servo artifact creature token.

Thraben Inspector

When Thraben Inspector enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Ingenious Smith

When Ingenious Smith enters, look at the top four cards of your library. You may reveal an artifact card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
Whenever one or more artifacts you control enter, put a +1/+1 counter on Ingenious Smith. This ability triggers only once each turn.

Scrap Trawler

Whenever Scrap Trawler or another artifact you control is put into a graveyard from the battlefield, return to your hand target artifact card in your graveyard with lesser mana value.

Portable Hole

When Portable Hole enters, exile target nonland permanent an opponent controls with mana value 2 or less until Portable Hole leaves the battlefield.

Oswald Fiddlebender

Magical Tinkering — {W}, {T}, Sacrifice an artifact: Search your library for an artifact card with mana value equal to 1 plus the sacrificed artifact's mana value, put it onto the battlefield, then shuffle. Activate only as a sorcery.