So, here's the long and short of it that I hope is a good summary:
There are 3 common film processes around now. There are some historical ones, but since these are only done by specialists if at all, I'll consider them mostly irrelevant.
1. Black and white. This is the oldest and simplest of the processes. Essentially, light sensitive silver halide crystals are suspended in gelatin(this part is called the emulsion) coated on a plastic support. When film is exposed, some quantum mechanical magic happens to those crystals. To develop the film, you first use a chemical called a developer, which turns the "exposed' silver halide crystals into metallic silver that clumps together into grains. After this is done, the film is "fixed" with a solution that dissolves any remaining undeveloped silver halide.
The end result of this is called a negative. Areas where light hit the film have a high build up of silver during developing, and if illuminated from the back those areas appear dark. Areas where no light hit have no density of silver, and they appear clear. Printing paper uses this same process, so when you project this "negative" image onto light-sensitive paper and then develop it, the end result is a "positive" image.
There are a handful of B&W films out there. Kodak and Ilford are the two major players, but not the only one. Film is rated by how sensitive it is to light-the ISO setting on digital cameras is intended to replicate film. IN GENERAL, the more sensitive to light a given film stock is, the larger the grains are after developing, and the less detail the film is able to resolve. Kodak and Ilford make two general types of film. Films like Tri-X, FP4+, and HP5+ have what is called traditional grain. The Kodak TMAX line and Ilford Delta line use "tabular" grain film, called T-grain in Kodak and Delta with Ilford because the grains have a sort of triangular shape. T-grain films tend to have less apparent grain for a given speed, but have a different look that not everyone likes.
There is no real standard for B&W development. There are some common developer formulae-Kodak D76 for example is an old standard that is often copied-and a lot of the common ones like D76 or HC110 work well for about everything. Fixer is generally either sodium thiosulfate("hypo") or ammonium thiosulfate("rapid fixer"). There are a lot of specialized developers, developing techniques, and all kinds of other variables. Within a given developer, different films have different times.
I don't have labs process my B&W film because realistically most can't adjust for everything. They'll tend to use something like D76 1:1 at 68ºF for 7 minutes, which will give a useable but not optimum image with everything.
2. Color negative film is probably the single most common type of film in the world. In addition to Kodak Gold, Fuji Superia, etc you have films like the Kodak Portra line. The latter are typically fine grained, low contrast films designed to render skin tones nicely and deal with complicated lighting situations.
The current color negative process is C-41, and the chemistry, temperatures, and developing times are all standardized for repeatable results with any film at any lab.
C-41 film works a lot like B&W. Basically, first of all, even modern B&W films have layers with different color sensitivities. The silver halide salts need some "magic" to make them sensitive to light other than blue. For a color negative film, you start with that but then add things called "color couplers" which appear when the film grains are developed. C-41 developing starts off just like B&W with a developer that will turn the exposed silver halides into metallic silver. It's fixed just like B&W film to remove undeveloped silver halide, and then "bleached" to remove all silver. This leaves behind only dye clouds, and they are the complimentary color of what was developed.
3. Silide film is process E-6. It's "built" like C-41 film, but there are some technical differences as well(C-41 usually has an orange tint, called a mask, to the film base that helps with printing. E6 is clear).
The developing process is even more complicated, though. Basically, it's developed with a conventional developer, but then bleached to remove both silver and with a bleach that will remove the dye clouds associated with it. This leaves behind all the unexposed silver halides, which are then "exposed"-either chemically or by just open the film up to light. It's developed again and then bleached and fixed. The second exposure/development "reverses" it so you get a positive image. These can be projected, or you can view them directly with a loupe and light table.
The above is all overly simplified, but that's kind of the run-down on it.
B&W done at home can be the least expensive of them, but lab C-41, even in 2021, can be really inexpensive. Even last year, I had a couple of labs local to me that would do C-41 process only(for me to scan at home) for $4-5/roll.
Specific films also tend to have specific properties. TMAX100, for example, is a very sharp and high contrast film. Tri-X(one of the oldest films on the market, and IMO one of the best all around general purpose B&W films) is somewhat less contrasty than TMAX100 but has very noticeable "gritty" grain that many people like. In color negative film, Portra films are low contrast and low saturation. Ektar 100 has a lot more "pop" to its colors Portra, but is less forgiving when shooting. Among slide films, Ektachrome E100 and Provia 100F offer moderate contrast, really fine grain, and pleasantly saturated but not over the top colors.Both offer slightly different color renditions(E100 tends to be a cooler film). Velvia, which comes in both 50 and 100, for a while was the landscape photographers' go to film. Velvia is very saturated-enough so that it's sometimes called "Disneychrome", a beast to shoot for how contrasty it is, and looks like nothing else when it's done right.
