Jisho.org Forum

思い出す is a verb, you don't add だ or です to verbs. The proper forms are:

思い出す (Short)
思い出します (Masu/Desu)

This is a little more technical than what is needed, but it's the best way to explain it. です is the polite form contraction of である. 二つであります。　＞　二つです。 In these sentences, です can be dropped in casual speech. Likewise, だ is the short form of です and can also be used in casual speech. 二つです。　＞　二つだ。 For some grammar points, short or masu/desu form is needed, but as a complete sentence, it can be excluded in very simple sentences. Like 'It's cold'　＞　さむい (だ)

だ/です usually follows noun, i-adj and na-adj. If you want to add だ/です to a verb to emphasize the situation/reason, you should use のだ/のです or んだ/んです.

なぜ来なかったのですか?/なぜ来なかったんですか? (Why did you not come?)
忘れてしまったのです/忘れてしまったんです. (Because I forgot.)

Yeah, I think だ/です is not needed for verbs, but you can add んだ or んです to the end to emphasize or confirm/explain the sentence.

Thank you for explaining!