Already is not a verb so does not have a past participle form.
Thought is already the past participle of "think".
"broken" already is the past participle of "break".
"Talked" is already the past participle, or past indicative, of "talk". "Talked" as such does not have a past participle, because it is not an infinitive form of a verb.
Sat already is the past participle of sit.
The past participle of prepare is (have or has) prepared. For example, "I have already prepared tonight's supper."
"Had" is already the past participle of "have".
Jumped is already the past participle of jump.
Tried is already in past participle form. It is the past participle of try.
Consumed is already in past participle form. It is the past participle of consume.
Thought is already the past participle of "think".
Imagined is the past participle of imagine.
"broken" already is the past participle of "break".
The past participle of submit is submitted
It is already in past tense.
Laid is already the past tense and past participle of lay.
Listened is already in past participle form. It is the past tense and past participle of listen.
Caught is already the past tense and past participle of the verb catch.