These came from a number of sets, including a handy "Decorated Elements" set that covered most of the printed parts from the mid-90s space theme.
However, Recon Robot appears to be the only one that contains two of the 2x2 tiles and only one of the 2x1 tiles.
Instructions can be found in a number of places, including on Let's Build It Again.
I actually managed to find the exact set while refining the question. It's set 744, released in 1980.
Here are the reasons why the research I did prior to writing the question didn't lead anywhere:
The yellow motor does not show up when searching parts on BrickLink. It's probably because on the list of set 744 parts, it has a note saying "Part colour ...
Not a great pun, but the 2016 advent calendar was:
40222-1: Christmas Build-Up
Sort-of a pun/double-meaning on LEGO being a building toy, and the set being meant to build-up to Christmas.
The 2017 version also has the same name.
3852-1: Sunblock (or Sun Block as styled on the packaging)
Here "Block" takes on 3 meaning, as part of the word "Sunblock", a pun on LEGO blocks (though I prefer to call them bricks), and a reference to the game play where you try to block your opponents from making another move.
It looks like the bulk of the parts are from The Chamber of Secrets (4730):
As Henrik mentioned, Sorting Hat (4701) is also present:
Jason pointed out that Dumbledore's Office (4739) is also present:
I thought it might be worth noting that these old Harry Potter sets are fairly valuable to collectors. The Chamber of Secrets alone in complete used ...
Those horses look like legit LEGO-brand horses.
White Horse with Black Eyes, White Pupils and Dark Orange Bridle Pattern: 4493c01pb04
Black Horse with Black Eyes Circled with White, Brown Bridle Pattern: 4493c01pb02
In order to be extra sure they are genuine LEGO, look for the "LEGO" stamp on the inside of the hollow studs on their back ...
The red car that you mentioned is Mail Van (7820).
There are a number of other trains in the picture including:
7730 - Goods train (the locomotive doesn't seem to be visible)
7710 - Push-Along Passenger Steam Train (just the cars)
7750 - Steam Engine with Tender (pulling the cars from 7710)
7814 - Crane Wagon
7760 - Diesel Shunter Locomotive
7720 - ...
Your best shot is to identify an individual piece and look it up on Peeron, BrickLink or BrickSet. Since these all carry set inventories, you'll be able to find lists of sets in which the parts can be found. Try to start with more unique parts, chances are they are in a few models only.
Once you're sure you've found a model for which you've all the parts, ...
These appear in 4s in many iterations of the Imperial Shuttle, and also many of the X-wing, as well as the
MT-201 Ultra-Drill Walker and the SP Undercover Cruiser. I can't say for certain which of these sets originally contained those pieces, but this should get you closer. This list also shows sets that contain the piece in smaller quantities.
After zooming the image and identifying the windscreen, I searched the Bricklink catalog and found the #4402 Sea Riders set in the list of sets using that windscreen in trans-black:
More details and instructions can be found here.
Possibly 31045 Ocean Explorer?
Red and Dark Blue
one model is a plane
If that's not it, you can browse Bricklink for sets containing hooks. I'm guessing you probably saw the modern "Hook with Towball" piece
The most obvious sign is the LEGO mark present on each stud. I have yet to learn of any single copycat company that would go through the legal and technical trouble required to mold these onto every stud of every piece in a consistent fashion.
If the piece has no studs to check or the markings are present and you still have doubts you can take a suitably ...
It looks like you have SandGreen parts from probably two different sets...
The dinosaur head (x158), 2 tail sections (40396 and 40379), 2 sloped pieces (3039), and black Technic brick (3700) are likely the remains of a Baby Ankylosaurus/Young Ankylosaurus:
The wedge plate (2419) and curved brick (6091) are likely parts from a Red Planet Cruiser (also in ...
Welcome! This collection of pieces might contain some LEGO pieces, but is mostly another brand. The bottoms of the bricks and plates have patterns that are not typical for LEGO, and LEGO does not make a large wedge plate like the light-grey one on the right. Furthermore, LEGO did never make a large tree stump and tree with face as shown in the middle of the ...
Based on your description, the set is Launch and Load Seaport (6542):
It was released in 1991, and it matches everything you described including a ship called "Atlantic", so this has to be it. If you're looking for some nostalgia, you can pick this up on Bricklink for ~$150.
The build on the left is from 60002 - Fire Truck - it's the turntable/mount for the ladder:
Based on containing the "Plate 6x6 round", and "Bottom W.Turntable 4x4"
The build on the right is from 60147 - Fishing Boat - it's one of the engines:
It's currently the only set with "Plate W. Bows 2X3½" in New Dark Red.
I believe that this covers everything:
Diesel Dumper (6532)
Landscape Loader (6512)
Recycle Truck (6668)
Friends car (30103)
Launch Evac 1 (6614)
Rescue Runabout (6511)
Looks like just the car from Shell Convenience Store (1254)