Learn French: La plupart des enfants aiment cette bande dessinée.

When using la plupart (most), the verb agrees with the noun that comes after it, not with the word plupart itself. Because enfants is plural, the verb must be the plural aiment.

We usually say beaucoup d'enfants. Why does la plupart use des instead of d' here?

Most expressions of quantity (like beaucoup, trop, or un peu) are followed by a simple de or d'. However, la plupart is an exception that always includes the definite article. Here, de + les contracts into des.

Is bande dessinée the most natural way to say 'comic book' in spoken French?

While entirely correct, everyday spoken French heavily favors the abbreviation BD (pronounced bay-day). You will very often hear people refer to this as cette BD.