what are the other books that Jules Verne wrote
Jules Verne wrote a lot of novels and a few short stories, and became famous already in his lifetime with them. A definitive list of his works can be found in the article about him on fr.Wikipedia. The linked section and the next one lists all the books published that he wrote. More than half of these books is science fiction, and more than half of them are really good and worth to read. En.Wikipedia has an equivalent list. The Jules Verne FAQ by Ariel Pérez, Garmt de Vries and Jean-Michel Margot says that the two most well-known books of Jules Verne are Twenty thousands leagues under the seas and Around the world in 80 days.
Most of Jules Verne's works went to public domain forty years ago; the few posthumously published novels that were edited by his son Michel Verne also went public domain more than twenty years ago. Because of this, you can find copies of all or almost all of his books on the internet. I recommend fr.Wikisource, where you can find copies of most of his original works. That page also has links to Wikisource sites in more than fifteen other languages that have some translations. Many translations are already public domain, but the best translations tend to be modern ones where the copyright term hasn't expired yet, but even these you can often find in libraries or bookstores cheaply. Project Gutenberg also has copies of many originals and translations of the books, although many of those have been copied to Wikisource.
The pages containing the original books on Wikisource also contain the original etchings used in the illustrated original editions of Jules Verne's books. These medium resolution scans of all of these etchings are available thanks to the crew of "The Illustrated Jules Verne" website. High resolution scans of most of the etchings are sadly not yet available on the internet. However, you can find many of the illustrations in later editions of his works that are readily available: many older translated editions from the 1890s were published with the original editions, and those older editions later got exact reproduction editions.
were the books filmed?
A lot of adaptations have been made of Verne's books, including many with shoddy quality. There are a lot of films based at least somewhat on his books. Donald Hosek already linked to IMDB's full list of known such films, and that's probably as precise and complete as you'll get. Fr.Wikipedia also lists selected film adaptations and other adaptations.
What happened to Arronax, the company, and Cyrus Smith who administered the last rites after captain Nemo's death?
Jules Verne describes Captain Nemo's death and meeting with Cyrus Smith in the sequel novel L'Île mystérieuse. Let me sum this up in short.
Cyrus Smith the distinguished engineer and four more companions escaped from a city under siege in a hot air balloon. The winds took the balloon to an uninhabited island. The five companions lived there for two years, together with Tom Ayrton, who got left on the neighboring island twelve years ago from another of Jules Verne's novels Les Enfants du capitaine Grant.
Captain Nemo, after all his companions left or died, parked his electric submarine in a cave inside the island. He's been secretly observing and helping the team of shipwrecked settlers, and has saved his lives several times. When he finally reveals himself and admits all this, he also tells that his submarine is stranded inside the cave, because the island is volcanic and the entrance of the cave has risen above sea level. Cirus Smith, meanwhile, informs Captain Nemo that they already know about his story from the protagonist of Twenty Thousand Leagues Under the Sea, Aronnax, who escaped from the submarine with his two companions and published the story. Captain Nemo dies in the submarine inside the cave, and the slowly sinking submarine becomes his grave.
The settlers are finally almost ready to escape with a raft that they are building, and dreaming of later returning to this wonderful island and start a small colony. All six, however, have to run to the raft before they can finish packing food, and barely escape the island, which is completely destroyed by its volcanic eruption.
