If you use a local copy of CardConurer to create your cards, you can use {fontsize-11} on the type line, and it should fit these card types exactly, along with an expansion symbol.
I agree with
@Rusje. At the very least you want to move Prismatic to the top. As an ability it should definitely read "in addition to its other
colors" since you could use this ability on any creature, including multicolored ones. You could also create a colorless legendary with two instances of prismatic. Furthermore, if you leave off the reminder text, I don't know that people will get what it does.
Personally I don't really like her abilities for multiple reasons. For one, putting a +1/+1 counter on all creatures you control seems
a lot stronger than all of the other abilities in terms of snowballing, but the red one is nasty too, as you're basically casting a recurring (as in every turn
and she's a commander)
Lava Axe for...
. That's where my main complaint comes in. Prismatic is all well and good to grant your players a little bit more flexibility in choosing their commander draft deck's colors, but Imoen basically is a mono blue card with a lot of very nonblue effects. In general, I think the abilities are a bit too strong on a 3/2 unblockable creature as well. Personally I would love this design way more if it played around with hybrid abilities, so
,
, {u/g}, and {u/w} effects and toned down the effects a bit. Bonus points if you ignore the conventional order and go in clock-wise order from the card's color.
I don't like the bulleted version as is, because that's not how Magic cards are worded, but you could very easily fix that by having it say: "If you do, choose one —". Sure, usually only one of the choices is going to actually do something so making it a choose one might seem moot, but as an additional bonus (besides using actual Magic lingo) you can't get multiple triggers with obscure effects like
Quickchange this way.
Two tweaks that can shorten your text a bit are to make the exiling mandatory, and to make the main ability an attack trigger instead of a combat damage to a player trigger. Imoen's unblockable, and 99% of effects that could remove her from combat, also can prevent her from attacking, so it's functionally pretty much the same.
Personally I would design her something like this...
Art link
(Maybe 3 lands is a bit much, but you can always tune it down...)