Small list of various features and examples of natlangs/conlangs that use them
Grammatical features are features that exist within a language and has been standarized into a grammatical feature which must be stated for the sentence to be grammatical and proper in the speakers ears, if it is optional or not standard it doesn't classify as grammatical.
Perfective and imperfective
Inceptive, continuative and terminative
Past and non-past
Past, present and future
Past, recent past, present and future
Past, recent past, present, near future and future
Past, present, near future and distant future
If its anywhere but "none" singular is always present as well and if it is anywhere but "plural" the plural marker is also always present aswell.
Morphological features are features that are directly marked and indicated onto the verb, noun or adjective
Person on verb
Subject and object marking