So I had this list stored somewhere, figured I might as well post it here :) Of the glitches, only Phantom driver could be remotely interesting for speedruns (afaict), and then mostly 100% I guess because it effectively removes random traffic.

Phantom driver Shoot at any car. As soon as the driver gets out of the car, immediately press [F1] for the replay effect then press the key again. The driver will be paused. You can even go through his body. You will notice that you cannot go into the driver's side of the door, but you can go in the passenger side if there was no one seated in it before. If you go inside the car on the passenger side you will be trapped there. Literally. The only way to get out is to suicide. Note: Do this glitch if you want to be hijack proof on the driver's side of the door. Cars and people glitched using this will not despawn, so repeating this a couple of times will effectively disable all random traffic (including police). This might be helpful for completing missions with police chases in them or for doing races at Sunshine Autos.

Hands free walk While holding [Up], press [F1] at the same time then press it again. You will be walking without having to press any keys. This is helpful if you are tired of holding the same key. Use the mouse the control the direction in which you are moving. Note: This can be also done in different walking directions with the keyboard -- just make sure you press [F1] while doing so.

Look backwards while driving Get inside of any vehicle. Hold [Down] to reverse and press the [F1] at the same time. Press [F1] again to exit the replay. Tommy will be looking backwards while driving.

Camera and replay of death (Extremely frustrating) This trick will allow you to pause time by the use of a camera and the replay effect. First, get a camera (Martha’s Mug Shot) and take a picture. As soon as you see the camera light flash, immediately press [F1]. Wait a few seconds then press [F1] again. As a result, everything in the game will move in extreme slow motion or be paused (not sure what exactly happens, a mission ped moves in slow motion, the time is paused). You can do a lot of extremely strange moves with extreme slow motion Tommy. When talking about slow motion, the game runs at less than 1% of normal speed. Perhaps this is influenced by the exact moment of replaying. To exit this glitch and return to normal time, retake a picture or shoot an RPG (or enable the bigbang code). Shooting an rpg also works. Note: You can still cycle through your weapons, but if you use them it will take a very long time to make a single shot because you are in slow motion and therefore cannot cycle through your other weapons again.

Invisible weapon inventory Go to any Ammu-nation or hardware store in Vice City. Walk up to the pink marker and immediately throw a grenade. The cashier will be dead and all of the weapons in the inventory list will disappear except for the Body Armour. You can however still buy the invisible weapons.

Strange point of view From the Film Studio's entrance, move directly south. You will see a coastline with some water touching over the grasses. Get further down into this water, so that the camera changes to a different angle, but stay close enough so that you do not lose health and drown of course. Use first person view with any weapon and go out of it. The game will zoom all the way to where the Leaf Links golf course is found (coordinates 0,0,0), and zoom back to where you are once you get far enough out of the water again. The camera will go to a weird angle using the near any water, but not quite so extreme.

Hold unknown weapons (requires cheat) While holding a weapon, enable a weapons cheat, then press [F1] for the replay effect. Then, immediately press [F1] again. You will be holding an "unknown" weapon. The weapon consists of everything in the scenery, such as trees, buildings, the sky, your surroundings, etc. To hold different "unknown" weapons, keep pressing [F1]. Note: This will cause your game to crash repeatedly exit to Windows. You will also get unhandled exception error messages because solid programming.

Martha's Mug Shot: Fast destination (requires cheat) Use the flamethrower weapon on the driver. He will come out of the Stretch. Wait until Candy approaches the vehicle. When she gets inside, quickly enable the fannymagnet code or press [Esc] first before enabling the code. The Stretch will move for a short second and Candy will abruptly come out of the vehicle and start to attract you. Get inside of the vehicle, wait for Candy to enter it again, and you will now have complete control over it. Drive to your destination and you will be there in no time.

Invincibility (requires cheat) As you open the door of a vehicle, quickly press [Esc] and enable any of the different costume codes of your choice. The result will be you being invincible to any attacks that hit you. Also, if you blow up yourself with a rocket launcher, you will still not lose any health or armor, but you will be just lying down pretending to be dead. To "wake" yourself up, enable the same or another different costume code again. Note: This is glitch is similar to the "Phantom driver" glitch because you are actually paused but in a form where the input devices can control your body; however you will not be able to move around anywhere else. People and objects can also go through your body.