[natalia91]

bear (someone or something) in mind- to remember and think about someone or something
absent-minded- forgetful

[zuzaa]

be all in the/your mind
if you say that a problem that is worrying someone is all in their mind, you mean that they have imagined the problem and that it does not really exist His doctor tried to convince him that he wasn't ill and that it was all in the mind.

[Dominika93]

I bought it with you in mind- kupiłem to z myślą o tobie

[diamona]

keep in mind - zapamiętać
wander in minds - bujać w obłokach

[anap4]

Mind your own business

[Adam Kowalczyk]

speak one's mind - to say frankly what one thinks (about something)

Mind your own beeswax - to mind one's own business

weigh on someone's mind - to be in a person's thoughts

[ingestre]

mind your p's and q's - to make an effort to be especially polite in a particular situation

[mogr]

be in/of two minds - to be unable to decide about something e.g. I was in two minds whether or not to come this morning.

contented mind is a perpetual feast - If you are mentally at peace, you will always feel that you have enough of everything, and will not have to strive to get more.

[pawelmichal]

to be bored out of one's mind - nudzić się jak mops

[Rammarg]

a frame of mind- the way someone feels at a particular time

cast your mind back- to try to remember something (usually + to )

prey on somebody's mind- if something preys on someone's mind, they worry about it for a long time