I would really recommend that you not mix frogs and snails together. Ditto on the gouramis, especially the aggressive ones that will hurt your snail (which is the same with most Bettas too).
Here's a list that I've found:
QUOTE
Corydoras catfish
Cory's are small, peaceful catfish which are ideal for the community aquarium. The commonly available species are generally hardy and easy to breed.
Examples:
• Albino/Bronze cory
(Corydoras aeneus)
• Peppered corydoras
(Corydoras paleatus)
Rainbowfish
Rainbowfish are colourful and active shoaling fish, which are often overlooked as community fish, probably partly because the juveniles seen in the fish store are not showing their impressive adult colouration. Dwarf species are suitable for smaller tanks.
Suckermouth Catfish/Plecos
These fish, popularly known as plecos, are an extremely docile fish. Active during the night, they will feed along with your snail. Smaller specimens may latch on to your snail, but there is no danger.
Khuli Loaches
Bala Sharks
Danios
Iffy Fish
Livebearers
This common species of fish is a good community fish and are hardy. These species include Platy’s, Guppy’s, Mollies, and Swordtail’s.
Barbs and Rasboras
These are an active and colourful addition to any community tank. Not all are peaceful, and some grow quite large, but the species listed opposite are ideal for the general community tank.
Examples:
• Cherry barb
(Barbus titteya)
• Golden barb
(Barbus semifasciolatus)
• Five-banded barb
(Barbus pentazona)
• Harlequin
(Rasbora heteromorpha
Dwarf Cichlids
Unlike many of the larger cichlids, the dwarf cichlids from South America, and some from Africa, are generally peaceful, and only become territorial when a pair are spawning. Most only grow to around 2" (5cm) long.
Most goldfish.
Aggressive Fish
Loaches
The loach species make an interesting addition to the community aquarium. The species listed below are sociable towards other fish and best kept in groups. Note that some other species of loach, includingt the clown loach, can be aggressive, especially toward apple snails.
• Clown loach (AGGRESSIVE!)
(B. macracanthus)
• Pakistan loach
(B. almorhae/lohachata)
• Zebra/Candy-stripe loach
(B. striata)
Paradise fish
Though small, they can be aggressive and aren't recommended companions of other slow moving fish such as Angelfish. Body color is dark red, with several blue vertical bands running along the fish. The upper body and head are spotted in black.
Bumblebee catfish
Relatively undemanding fish. They are primarily nocturnal, but once well-settled in an aquarium and given retreats, they will venture out and be seen looking for food. Although peaceful towards most fish, individuals may be territorial toward one another, and very small fish are regarded as food.
Puffers
I've kind of added to the list as I've found information. I got this off the "Apple snails, fish and plants" section of the Applesnail.net discussion board.
With goldfish, it's kind of a hit-or-miss thing. Some people have kept goldfish peacefully with snails, but I've not had that experience. My goldfish continually pecked at my snails' antennae and soft bodies, eventually (I think) causing fatal mantle collapse in my gold, and possibly contributing to the death of my adult blue (this was while I was on vacation so I'm not totally sure, but she nipped off an antennae of the gold previously). It basically depends on the goldfish, I think.
The heater malfunctioned and the temp of the water got way too high way to quickly before we could save him. We did everything we could but it was too late. Anyway, Riddley, the snail, is now in the tank all to himself. I am wondering what your thoughts are as far as tankmates. I have two other bettas, in their own tanks, and will probably end up getting another one for Riddley in the end, but I do worry that I will get the one that is overly aggressive and picks at him. 
Are there other types of invertabrates that would work well with him? I worry about getting another apple snail because I don't want a ton of babies later on. (I'd have no where to put them). 
I'm not sure how many babies they'd have but I only have three other fish tanks and I wouldn't want to cram a snail into a five gallon or put it in with the orandas.... they tend to eat anything that hits the water...even your hand. 
then scrape and flush the eggs..Linda
And since we like the apple snails so much we may just take our chances and get another and hope it's the same sex as Riddley...even though we don't know what he is exactly (I saw on applesnail.net how to tell the differences but am having difficulty seeing it)