My favorite is, "Why don't you make like a tree and go fuck yourself?"

Does the pope shit in the woods?

Bob’s your oyster

"This is a tough nut to swallow"

"It's not the end of the day"

When life gives you melons, you might be dyslexic.

Don't count your chickens before you put them all in one basket

You can beat a dead horse but you can't make it drink.

From the Buffy-verse.

Harmony, the dumbest vampire.

"You're preaching to the horse's mouth."

You opened this can of worms, now lie in it

I resent, and resemble, this

Oh yeah! How could I forget:
"Get two birds stoned at once"

A bird in the hand is worth two with one stone.

"Yesterday we were at the brink of abyss, today we took a step forward"

"It's a dog-eat-dog world out there, and I'm wearing Milk-Bone underwear."

"People who live in glass houses can count their chickens in the rain."

"We'll cross that water when it's under the bridge."

I'm fond of "not the brightest cookie in the knife drawer"

Bojack Hosreman had a couple of good ones. My favorite was: “Fool me once, shame on you, but teach a man to fool me, and I’ll be fooled for the rest of my life!”

I'm here to kick ass and take names, and I'm all out of ass!

*clicks pen*

Names, please...

One I accidentally said a while back and now use for anything that's both unhinged and comes out of nowhere: Out of left pocket

Why does this screenshot look like a highschool teacher photocopied it from a book?

From I Love Lucy... Ricky tried giving Lucy an ultimatum in his broken English...
"Don't cross your bridges before your chickens have hatched!"

You: Do you know what malaphors are?

Me: Does the pope shit in the woods?

Light a man a fire and you warm him for a night. Set a man on fire and you warm him for the rest of his life!

Does a bear shit in the pope's hat?

Oh, we have those in German too:

1st Idiom: Life is no pony farm
2nd Idiom: Life is no sugar-licking.

Both meaning life isn't easy.

Combines into: Life is no pony-licking

One hand washes the other.
One crow doesn't pick the others eye.

The former meaning: "Quid pro Quo" and the latter: "One scoundrel doesn't tell on the other."

Combines into: One crow washes the other.

Like an elephant in the china shop. (The proverbial bull in the china shop)
Who's sitting in a glasshouse shouldn't throw stones. (If you are yourself vulnerable to / guilty of the allegation, don't throw the proverbial first stone)

Combines into: Who's sitting in a china shop shouldn't throw elephants.

Who digs a pit for another will fall in themself. (Meaning is obvious)
Who's sitting in a glasshouse shouldn't throw stones. (As above)

Combine into: Who's sitting in a glasshouse will fall in themself.

Had a pig. (That was lucky)
Sponge over it. (Erase it / it's okay / forget it)

Combine into: Pig over it.

Note: in German sponge (Schwamm) and pig (Schwein) begin with the same syllables.

Not seeing the forest for the trees. (as in English)
Standing like the ox in front of a mountain. (being baffled or at a loss)

Combine into: Standing like the ox in front of a tree.
Or: Not seeing the ox for the mountains.

Hitting two flies with one swatter. (As in two birds, one stone)

Morphs into: Hitting two swatters with one fly.

Better the sparrow in your hand than the pigeon on the roof. (Be content with what you have in your hand instead of going for the bigger thing that's harder to get.)

Morphs into: Better the mute (woman) in bed than the deaf (woman) on the roof.

Note: "Die Taube" is feminine and can mean both "the pidgeon" and "the deaf". (dove, deaf, you can see the connection in English still)

Better the sparrow in your hand than the pidgeon on the roof. (As above)
Shooting cannons at sparrows. (Overreacting)

Combine into: Shooting pidgeons at sparrows.

There's no use crying over fish in the sea.

Much fun, but IMO "we'll burn that bridge when we get to it" is a perfectly valid maxim (yes I'm aware of its roots). YMMV.

The road to hell is paved with hand-baskets.

I got in trouble at a corpo job for saying "We'll jump off that bridge when we get there."

get two birds stoned

One of my favourite ones in Bulgarian is "Око за око, паста за зъби".

"Око за око" is "an eye for an eye" and "паста за зъби" is literally "paste for teeth" (or what we say for "toothpaste").

The latter is technically not a saying or an idiom, but I think it still works. I believe I don't need to explain the absurdity of it.

You can lead a man to water but you can't teach him to be a horse

You're barking up the wrong metaphor.

I have a t-shirt that says "It's not rocket surgery" and depicts a surgeon working on a rocket with it's "guts" hanging out that are wires. I'm actually wearing it now, lol.

People who live in glass houses sink ships.

Speaking of bridges, I like "cry me a river, build me a bridge, and get over it!"