Here, have Isona, the new planeswalker from the Boom! comics. That's Isona in her first appearance on the left and in the last one on the right — these are both top-down with the idea that Isona is a colorless planeswalker and that her signature power is to be an amplifier or dampener for aether access.
(Some rule interactions:)
Isona Maive
You can cast Isona from your graveyard any time you could normally cast a planeswalker.
Isona’s abilities are linked. If another permanent gains those abilities, the last ability will only copy cards that were specifically exiled with the other three.
The last ability causes you to sacrifice Isona even if you she has 11 or more loyalty counters on her as you activate it, or would otherwise survive paying its activation cost. If she is still on the battlefield, you will sacrifice her as part of the resolution of the ability.
The cards you can copy with the last ability are all those that were exiled with Isona at the point she left the battlefield, whether during paying the cost or as you sacrifice her.
If you cast spells with X in their mana cost with the last ability, X will be 0.
Isona, Seeker of Fate
Isona’s first ability can cause the opponent to be unable to activate mana abilities.
Isona’s abilities are linked. If another permanent gains those abilities, the last ability will only let you choose spells or abilities noted specifically for the other two.
You do not need to write down the full ability or spell — just note down what card it was, and, if needed, whether it had gained any abilities from other sources.
As Isona’s third ability resolves, if you choose an ability, you will perform all steps of activating it except paying its cost. You will choose targets or modes for each of them and each of them will go on the stack if it's not a mana ability. (You will just resolve it immediately if it is a mana ability.) If you choose a spell, you will not pay its mana cost, but you will pay any additional costs. Isona will have that ability while you are activating it, and will lose as soon as activation finishes.
There is no moment during or after activation in which you can activate a noted ability again after you start resolving the last ability. You will not have a window to activate mana abilities during that activation, since you will skip paying the ability's cost.
If you cast spells or activate abilities with Isona's last ability, and they have a cost with X in it, X will be 0.
If you activate an ability with Isona's last loyalty ability, and that ability expects some information from another linked ability, it will not find it. The information will be undefined and the part of the ability that refers to it will not work. For example, if you copy another Isona, Seeker of Fate's third loyalty ability, you can't choose any noted spell or ability.
If you activate an ability with Isona's last loyalty ability, and that ability requires you to exile, choose or note something, the choice is lost as soon as Isona loses the ability after activation. It will not be available to future activations.
If you somehow activate the last ability without having noted any ability or spell, it will do nothing.