Lost But Found - 100% Achievement guide

Tips

Two upgrades to get early: The court papers so you don't have to leave money for the family, and the cash register to stop the robber from stealing your money (unless you're going for the "Robbed barefoot" achievement).
Right-click and drag the table to move along it, especially useful if you've upgraded the size.
Items will only spawn if they're not already on the table. If you're looking for a specific item (e.g. the combination lock bag or stickers), filling the table with other items will increase the likelihood of it coming up on the belt.
Stickers left on items at the end of the day will re-roll the next morning. You can save and load the game to speed the search up even more. Once you've collected a missing sticker, remember to complete the day to permanently add it to your sticker book.
No customers will spawn if you don't have any items on the table (good for grinding 100 days).

Story achievements

Rookie rush.

Complete day 1.

Newbie no more.

Complete day 10.

Basically a pro.

Complete day 25.

The grandmaster.

Complete day 50.

The chosen one.

Complete Day 100. Once you have enough money, you can grind this (more or less) passively by emptying your table and letting the items on the conveyor belt get trashed automatically. You'll just have to start the new days.

Hero of our people bronze.

Return 25 items.

Hero of our people silver.

Return 50 items.

Hero of our people gold.

Return 100 items.

Hero of our people platinum.

Return 250 items.

Hero of our people diamond.

Return 500 items.

Return of the returner.

Return 1000 items.

Magnum opus.

Complete the game by reaching 30,000$ and use the bank. You'll lose you're progress, so I would recommend doing this one last if you're achievement hunting.

Shackles of Shame.

Leave money for the family. You can avoid this by upgrading the court papers. Lose the game by not leaving money for the family. Simply deny leaving the family money 4 times at the end of the day. At the beginning of the next day, you'll lose.

Dom says "family" 33 times in the movie.

Leave all your money at the house on the first day. The goal is to end the day with exactly 60$. The easiest way I've found is on a new "chill" game. Keep moving items from the conveyor onto your table until you get enough interactive items, marked with a red exclamation mark. Each time you complete a minigame, you'll receive exactly 10$. Once you hit 60$, wait out the rest of the day and then pay the family.

Robbed barefoot.

Loose the game by hitting zero money from being robbed. The robber only shows up when you have around 110$ and takes a percentage of your money. One way to get the achievement is to have the minimum amount of money for the robber to spawn, and then trash a bunch of high-value items so that the next robber deduction takes you to 0$.

Minigame achievements

To play a minigame, right-click items marked with a red exclamation mark.

Level one.

Complete a minigame.

Now we're playing.

Complete 10 minigames.

The gamer.

Complete 50 minigames.

The player of games.

Complete 100 minigames.

Is this really my job?

Clean an object. Look for clothes with a red exclamation point. Right click to interact, then drag the sponge over the dirt spots.

Is this legal?

Sign a paper. Right click a document with a red exclamation mark to interact with it, then click and follow the indicated signature line.

Red wire roulette.

Defuse a bomb. Bombs are found in the locked silver briefcases. The lock has three digits that can each be either 0 or 1. Just try the different combinations until you open it. The correct order to defuse the bomb is shown by the 3 coloured dots above the cable connections.

Oops: BOOM!

Fail to defuse the bomb. Bombs are found in the locked silver briefcases. The lock has three digits that can each be either 0 or 1. Just try the different combinations until you open it. The correct order to defuse the bomb is shown by the 3 coloured dots above the cable connections, so cut them in a different order.

Shop achievements

"Lost" but "found".

Buy something from the Black Market.

Black baron.

Buy all items in the black market. The achievement popped when I returned to the Black Market the next day after buying the last item.

Shady.

Increase Black Market level to 10 by putting items into the cardboard box when the Black Market guy requests items. The end of day report will show how many points you've gained under "Black Market score increase. (You can then sell the items at the black market at the end of the day for cash.)

Retail therapy.

Buy something from the store.

Maximum space.

Upgrade the table 3 times to reach the maximum size. You can buy the upgrade from the shop for 2400$ each.

DJ for a day.

Buy the M4ZO Music Player from the shop for 300$. The next day, place it on the table and click it to change the song.

Shelf-obsessed.

Buy all items in the shop. The achievement popped when I returned to the shop the next day after buying the last item.

Guardian of the gates.

Increase security level to 10 by returning items requested by the police officer. The end of day report will show how many points you've gained under "security score increase".

Misc achievements

Not enough items.

Have 20 items on the table.

Three's a Crowd.

Have three customers at once. This will happen automatically as you progress.

Call me maybe.

Call a customer to return an item. You'll get the number on a note when you tell a customer you don't have their item yet.

Spray and pray.

Fend off the criminal by spraying them with the mace. Drag the green spray can over them until the progress bar is full and they go away.

Welcome to plastic elo.

Throw a plastic bottle into the trash can.

Rotation salvation.

Reset the rotation of 10 items. To reset the rotation of a skewed item, click and hold the item, then press the tab key.

What's your emergency?

Type 911 in the phone and then # to call.

Is mayonnaise an instrument?

Return a kalimba to the black market person or the person saying "Give me something".

Sticker achievements

Stickers appear on four items: Luggage, Gaming laptop, Notebook laptop and Water Bottle. Collected stickers are saved at the end of a successful day and persist between games. I've added screenshots of the stickers to help determine what's still missing.

Stickers left on items at the end of the day will re-roll the next morning. It may be worth leaving them overnight to help you find the last few missing ones (or save and load the day to speed it up). Remember to complete the day after finding a missing sticker to permanently add it to your sticker book.