"a little plus sign inside the circle part of the lockhole"
Sure if it is a normal real door, but how about a Blast door with Reverse Lockhole, which simple doubles your key amount if you have positive amount of keys, and imagine doors, which only have door sprites for 1i, 2i, and 3i doors?
I think the Maroon Doors should be immune to Maroon effect and so on the other dark colors instead.
I was thought a Forest 5-door would become unable to open them in the "classical" way but I found they can be opened if you have at least 1 Green key so it cancels the Forest area with the difference rule. Sorry for this.
You will need at least 2 doors to do it. A door with 2 orange spend color and a buffer color that stores -2 keys from the 2 orange keys, then use that buffer color to give 2 orange keys.
Red doors (and any door with Red on it, such as a Bicolored Door with a Red spending color or a Combo Door with at least one Red lock) are immune to the Maroon aura and vice versa, Green doors are immune to the Forest aura and vice versa, and Blue doors are immune to the Navy aura and vice versa.
I think this is not reliable because there are frozen red blank doors (and other blank doors of those aura colors) in the original Lockpick. I think the Maroon Doors should be immune to Maroon effect and so on the other dark colors instead.
Reverse lockholes: A door with pink lockholes that requires POSITIVE keys to open, but instead of SUBTRACTING the key of the following color it ADDS the key of the following color.
Its negative variation is a door with cyan lockholes, which requires NEGATIVE keys and SUBTRACTS keys.
Convert keys: A key object that convert all the key of one color to another. For example, picking a pink -> cyan Convert key while you have 2 pink keys and 3 cyan keys will make it become 0 pink keys and 5 cyan keys.
Keepable keys and doors: A key or door that can be not interacted if a certain button is pressed. If it is a key the player can pass through without collecting it, while if it is a door it will not be opened and can blocks player.
Variable keys and doors: A key or door that can changes its key amount in a certain situation, or changes its color, or even appearing and disappearing, and many more.
Its possibility is endless!
Tricolored doors and doors of more colors: Similar to Bicolored doors, it will modify the key count of ALL the colors in its outer border.
Simple doors: A door that can only be opened if the key count of the following color is not a complex number. For example, a Simple door can be opened with 0, 3, -2, 5i or -1i keys, but not a complex number of keys like 1+2i.
Its variation is Complex door, which can only be opened by a complex number of keys.
Unstable Glitch keys: A new key type that can changes its color even after collected, and it will treads as the color of the last door opened.
Dispel aura effect: A weird aura effect that make the affected doors cost nothing after opened. The base cost of the door itself still need to be afford before it can be opened.
EDIT: 2024/07/13 Glass Doors: A door variant that has transparent looking, when you met its requirement, you break it as normal and cost your keys normally when you touch it, but if you do not met its requirement, you will break it without costing anything. For example, touching a Glass Orange 6 door when you have 6 or more Orange keys will open it normally and cost you 6 Orange keys, but if you have 5 or less Orange keys you will break it too and let your Orange keys unmodified.
Those doors use the glass-breaking sound exists in I Wanna KeyPick 100, played when you open a door that costs negative number of keys.
Silver Keys & Doors: A third key and door type that have glowing animation as Master (Gold) and Pure (Platinum) keys. The Silver Doors can be opened by Master Key charges but can not be cursed, as Master Doors can be cursed but can not be opened by Master Key charges, and Pure Doors can not become both.
