Metal & Spaghetti Monsters

Let's take a look at some of the artifact and colorless cards I think you should be including in your decks.  We even have access to Eldrazi titans!

Robots

To get started with your collection of retro cards, I recommend starting out with a couple of artifact decks.  I think the Brother's War precons are a great way to get started.  Once you have those, start to acquire artifacts that would be great in any deck! Wurmcoil Engine & Myr Battlesphere are incredible creatures in most situations.  If you are building a 5-color deck, Scion of Draco is a fantastic addition especially now that we have shock lands in retro frames.  Metalworker is a house for mana ramping but is also quite pricy as it is on the Reserve List.  Diamond Lion is a fun addition to commanders like Chainer or Alesha.  Steel hellkite is a card that I aboslutely adore, especially if you are ever able to do "the thing".  It is also great tech against treasure/food/clue decks.  Unfortunately, Steel hellkite is a removal magnet.  Platinum Angel does a great job of making you feel invincible!  It is two permanent t ypes so it is pretty easy to remove, but again it must be removed.  Sometimes I honestly like putting cards in my deck that will eat a removal spell as a way to protect other pieces.  Psychosis Crawler will slowly ping your opponents to death in any deck that draws a good number of cards.  Ornithopter of Paradise can go in literally every deck and you would never be upset to see it.  At the very worst, it blocks a flier.  Junk Diver and Scrap Trawler are a lot of fun, especially in a deck like Teshar.  Solemn Simulacrum was a staple in the commander format for many years.  If you are able to put it into a deck where you can take advantage of dies triggers or enter the battlefield triggers it becomes a great clog in your machine.  I am not too high on Burnished Hart but it is a great budget card and it has it's uses. 

Artifacts

There are so many great artifacts out there, even with the limitation of using only retro frame cards.  The three altars (Altar of Dementia, Ashnod's Altar, & Phyrexian Altar) are all in retro frames, Retrofitter Foundry was a judge promo and is great in any artifact deck.  Mycosynth Lattice is part of two two card combos (Mycosynth Lattice + Vandalblast) or (Mycosynth Lattice + Karn, the Great Creator).  Both of these combos are nasty and will leave your opponents with little they can do.  As a precaution, I would always let your opponents know you have these combos in your deck as part of the Rule 0 conversation.  helm of Possession is a card that I think should get a lot more play than it does, it enables death triggers while stealing the best creature on the board.  Soul-Guide Lantern is what I feel to be the best grave hate in the format (if you are only sticking with retro frame cards).  What I like about it is that it's not a static effect.  A card like Rest in Peace is certainly better but feels bad for your opponents.  This effect is one and done and at the very worst you can cycle it away for a new card.  howling Mine & horn of Green are group hug staples, I would never play them in any other strategy.  Memory Jar & Lifeline are both on the reserved list and be a little on the pricy side but are really fun cards to play. Mesmeric Orb fuels so many strategies, it is nasty in Chainer, Alesha, Bruvac, or Syr Konrad deck.  Also, it just effects your opponents as their key pieces find their way into the graveyard.  I would always be sure of what your opponents strategies are before playing this card though... Maybe don't play it if your opponent is playing Muldrotha?  Scroll Rack is fantastic is pairs classically with Land Tax (one of the #1 cards I recommend buying if you are going to live the retro life) and fetch lands.  

Equipment

There aren't very many equipment cards printed so far in retro frames.  Because of this, you would be hard pressed to build a strong equipment commander deck at this time.  As of right now, the only swords printed in retro frames are posted here and can command a hefty price tag. Skullclamp & Swiftfoot Boots are welcome additions though.  If you are trying to play a lot of equipment, maybe consider Sram as a commander or Tiana.  At this point, we are also lacking a lot of the great support for equipment that has come out in recent years.  You are able to pair up Sword of Feast & Famine + Aggravated Assault for infinite combat steps if you are looking to go that route.  

Weird Stuff

Null Elemental Blast should just read "One colorless - Destroy or Counter Target Commander". This card is fantastic!  If you use pain lands and talismans, you should be able to pay the one colorless.  It That heralds the End is a really cool card that I would put in an eldrazi deck.  Karn, the Great Creator is a really cool card but is not often fun for your opponents.  The reason is Mycosynth Lattice which will essentially shut your opponents out of a game of Magic.  

Legends

It's so cool that we got Eldrazi titans in retro frames!  While these guys are not nearly as strong as the previous versions of them, I think they are still formidable.  Karn, Legacy Reforged is a house.  I've only run it in the 99 so far but I imagine it would be a formidable commander.  As of now, these 6 legends are the only colorless options we have so hopefully one of them strikes your fancy!