Modifying all (occasionally each): mostly, for the most part. Obsolete.

Mostly all, nearly all; for the most part. Obsolete.

For the most part.

With respect to the majority of individuals or cases; for the most part; widely, extensively.

(Relatively to others.) Principally, mainly, for the most part. (Usually with the force of ‘mainly but not exclusively’.)

Modifying the verb or predicate: mostly; for the most part, mainly. Now regional (chiefly Scottish and Caribbean).

Chiefly, principally. archaic.

For the most part; on the whole, usually.

In all essential characters or features; in essentials, to all intents and purposes, in the main.

To a prevailing extent; predominantly; frequently, widely, generally, usually.

For the most part, mostly; almost.

Mostly, for the most part, usually.