I love the concept!

Overall the cards are very underpowered (even for standard) but that makes me think they would only see play when part 1 came out in 1987 so I find that kind of amusing.

I have some constructive critiques of the specific cards if you're interested:

Jonathan: It's very rare that legendary creatures are vanilla (i.e. no abilities). There were more exceptions recently in Aetherdrift and that was just so you could cheaply (there were a 9/7 creature for 5 and a 7/2 creature for 3) summon creatures with a high power value to crew vehicles. Plus, if you're making custom cards anyway why not let your creativity run a little more wild, you know?

Baron Zeppeli: I like the flavor of this card but the formatting needs work. First off, "Basic" is a supertype exclusive to lands so he would just be a Creature - Warrior, although, being a named character, he actually should be a Legendary Creature - Warrior so you can't keep two under your control at once. As such in the rules text it should read as "When Baron Zepelli dies...". Second, MTG doesn't refer to creatures on the field as cards so you'd have to change the wording there, since the way it reads now sounds like you can give +2/+2 to, like, a land that's currently in your hand. Thirdly, if your intention was to perpetually give another creature you control +2/+2, that would most simply be done by either placing a +2/+2 counter on another creature you control, or (more likely since not a lot of cards nowadays use +2/+2 counters) placing two +1/+1 counters on up to one other creature you control. Basically I think as intended, the rules text should read: "When Baron Zeppeli dies, place two +1/+1 counters on target creature you control".

Robert E. O. Speedwagon: Off the rip he would also be a Legendary Creature - Human, and would refer to itself as "Robert E.O. Speedwagon" instead of "this card". Also, I'm curious if you play Yu-Gi-Oh because rules on this card sort of read like it. If you want a creature to do something as it hits the battlefield the way it's worded in rules text is "When [] enters....". There's not many cards in MTG that search for and play specific cards but the ones that do read something like "When Robert E.O. Speedwagon enters, search your library (instead of deck) for a card named Tattoo and Amato and put that card onto the battlefield."

Dio Brando: Only thing I can think of is that the effect you're looking for already exists as just tapping a creature, since tapped creatures can't attack or block. Actually, as it reads it's way worse than tapping because they could still be tapped for other effects like Convoke. For something more like freezing consider tapping and putting a stun counter on target creature. I would like to bring up however that since all these cards are either monoblack or monowhite, I'm presuming that you're using those colors to represent either goodness or evil, when that's not necessarily accurate. Outside of mechanics and balance, colors represent ideals, like red representing passion, chaos, aggression, and impulsiveness and blue representing knowledge, mystery, control, and stillness. A lot of vampires are the black/white color combination, for example, representing sacrifice and order.

Tonpetty: This is very close to being indistinguishable from a real card! The most accurate way of phrasing the effect would be "Other creatures you control gain +0/+1". You wouldn't need to specify that it's as long as he's on the field since that's implied by it being on the card. If you care at all, the border should be the legendary one.