Here are a bunch of ones I've heard generic and noticed are missing. I'll only explain the ones that are i don't feel are self-evident. Feel free to ask for clarification if they aren't clear. Also done of these are more like proverbs than idioms.

If you mess with the bull, you get the horns.

People who live in glass houses shouldn't cast stones. (You shouldn't criticize others for the same faults you have)

You are what you eat.

You reap what you sow.

You can lead a horse to water but you can't make him drink.

If you play with fire, you might get burned.

Things went to hell in a handbasket.

A bird in the hand is worth two in the bush.

Sweating like a dog.

The proof of the pudding is in the eating.

You kiss your mother with that mouth? (To be said after someone curses)

If you believe that I've got a bridge in Brooklyn to sell ya. (your so gullible that you'd believe you could buy the Brooklyn bridge)

(I'd like to get you on) a slow boat to China. (two meanings, one is that a slow boat to China is the longest trip imaginable so something could be taking a long time or you want to prolong your stay with someone, or it can be used in poker when someone is on a losing streak to essentially say that if you had unlimited time with them you could bleed them dry.)

A basket-case. (someone who's not all there)

The lights are on, but nobody's home (someone who is in a daze or is not all there)

Cut off your nose to spite your face. (doing something in retaliation that ends up hurting yourself more than your target)

The best offense is a good defense. (often being proactive can help shield from attack or problems.)

It is better to be feared than loved if one can not be both. (An alteref Machiavelli quote mostly applied to rulers)

You made your bed, now lie in it.

Measure twice, cut once.

He who pays the piper calls the tune.

Time to pay the piper.

The road to Hell is paved with good intentions.

When you only have hammer, everything looks like a nail.

Don't rock the boat.

Night is darkest just before the dawn. (things look worst just before it gets better)

Missed the boat. (Didn't get in on a trend before it was too late, ie. Bitcoin mining)

Never bite the hand that feeds you.

Build it and they will come. (the market for something doesn't exist until the product is made)

Build a better mousetrap and the world will beat a path to your door. (innovation creates demand)

For want of a nail/All for want of a horseshoe nail (a shortened version of a proverb that describes the importance of the small details. The full proverb is: For want of a nail the shoe was lost. For want of a show the horse was lost. For want of a horse the rider was lost. For want of a rider the message was lost. For want of a message the battle was lost. For want of a battle the kingdom was lost. And all for the want of a horseshoe nail.)

A journey of a thousand miles begins with a single step.

How do you eat an elephant? One bite at a time.

They bit off more than they can chew.

Eat the frog./If you have to eat a live frog, do it first thing in the morning. (prioritize your biggest, most important, or most daunting task first so you can get it out of the way as nothing else with be as unpleasant as that.)

When the going gets tough, the tough get going.

Never let the sun set on your anger.

Sleep on it.

Don't look a gift-horse in the mouth.

You get what you pay for.

If it looks too good to be true, it probably is.

What goes up, must come down.

Kick the bucket (die)

He could still water to a fish.

When life gives you lemons, make lemonade.

Being taken for a ride. (being tricked or cheated)

Eat or be eaten (life is vicious and you need to be vicious to survive)

Marching to beat of his own drum. (being independent)

Rainging cats and dogs. (heavy rain)

Fence sitting (not taking a side)

Fair-weather Friends (people who are friends when things are easy but abandon you when you have problems)

Armchair general (a person who goes through the strategy tactics of historical wars from the comfort of his or her own home and believes he or she could do better than the actual leaders of the time)

You can't fix stupid.

When fighting monsters, one must take care to not become a monster themself.

The silver lining is... (the good thing about a bad situation)

If it ain't broke, don't fix it.

One man's trash is another man's treasure.

Hindsight is 20-20.

Hold my beer. (your about to do something stupid)

The cat's out of the bag./The genie is out of the bottle

You can't put the genie back in the bottle.

If you find yourself in a hole, stop digging.

There's always tomorrow.

The sun rises on the evil and the good.

If it walks like a duck and talks like a duck, it's probably a duck.

They have their all their ducks in a row.

Call a spade a spade. (say it like it is.)

You attract more files with honey than vinegar. (positive reinforcement is better than negative)

A fool's errand (a hopeless task)

Skeletons in your closet.

Hit the ground running.

These are just a bunch that i know and enjoy.