by heart 

Used to describe something you have memorized

It's a misnomer of course, but one that's used all the time

Do you know Danny's number by heart?

by heart by contagion; June 16, 2009

to know anything off by heart 

To learn something and keep it in mind for a longer time.

Synonyms:
To memorize
To learn by heart

Andy knows that it isn't easy for him to know anything off by heart.

to know anything off by heart by SmokingSkull January 22, 2011

Off by heart

Usually used in UK.
If you know something by heart, you can remember all the words in it without any help.
Learned in such a way that you can repeat it from memory.

We learned long passages of poetry off by heart.

Off by heart by Dudu2805 February 3, 2019

i know you by heart

I know you ! (VERY WELL)

- I know you love Hannah !!!
- No I don't ..
- Oh stop I know you by heart ! You can't lie to me 😂

i know you by heart by Pascal cœur October 21, 2017

Alice By Heart 

A musical written by Steven Slater and Jessie Nelson which made its off-Broadway premiere at the Newman Mills Theatre in 2019. This show puts a heart wrenching twist on the well known story Alice's Adventures in Wonderland.

Rosalynn: "have your listened to Alice By Heart? It's my favorite musical!"

Nicole: "No, but I'll check it out!!"

Alice By Heart by St.berry anti May 4, 2021

Heart attack by Chuu 

When you want to say you’re gay without saying it.

“do you listen to heart attack by chuu?”

“Or course”

Heart attack by Chuu by heychloe19 March 20, 2021

heartaches by All Bowlly 

THE BEST SONG IN HUMANITY

-yo the song heartaches by All Bowlly is perfection

-agreed

heartaches by All Bowlly by Nick fuentes March 27, 2023