Just for fun ...

奀 and 嫑 aren't really used in the real world.

Ordered according to their frequency on 百度:

否 [fǒu] = 不 + 口 (e.g. negate) | 77,900,000
歪 [wāi]= 不 + 正 (e.g. askew) | 54,400,400
甭 [béng] = 不 + 用 （不用) | 9,700,000
丕 [pī] = 不 + 一 (big) | 7,830,000
孬 [nāo] = 不 + 好 (bad, cowardly) | 3,860,000
奀 [ēn] = 不 + 大 | 370,000
嫑 [biáo] [báo] = 不 + 要 | 195,000
盃 [bēi] = 不 + 皿 = (same as 杯, often used for trophies) | frequency unknown

Do you know more?

By the way, if you study 繁体字, you can also add

覔 [mì] = 不 + 見 (look for)

to the list. For 简体字, it doesn't work (觅).

I see alot of those words are marked "will add soon" when I put them into a list to study, and all with the same pinyin. Why is that?

Some of the characters are quite rare, so they haven't been added to the Skritter database yet.