I have seen the five declinations in groups, but I didn't call it a list. i.g. the most animals are en-words. Undantag: ett djur (an animal), ett lejon (a lion), ett får (a sheep) and ett lamm (a lamb). Do you any other "ett" animals? And the ending -ing (+ some others) are always en-words: en släkting - ar (a relative), en utlännig -ar (a foreigner ). Best to follow Zrmzlina' advice. If someone is quick to find, a link in English would be nice. Part of us like a different kind of ways to learn, i.g. memory rules or grouping. I have tried several methods. I haven't found a real chat club. In my clubs, close to all seem to think about their own achievements and maybe leaderboard. That is okay, but... I really tried to be initiated in the other club, maybe I set too little questions. I am not an official keeper! My language skills are not good enough in the language of the other club. The clubs are there in the DL mobile. I would like to chat... because of the languages. And fun. Have a nice time with Duolingo!
I found this link helpful: https://www.swedishfreak.com/swedish-language/learn-for-free/en-and-ett-in-swedish/amp/
Scroll down to the tips section. There is a chart that shows the percentages of words that are en/ett, and it's based on the last letter (100% of words ending in -ka are en words). No idea how accurate it is. But it's a tool that allows you to make an educated guess. Combine that with the memorizing one word at a time approach and it might give you a slight advantage. It's a completely different way to learn but might be helpful if your brain likes to compartmentalize in groups.
Happy Swedishing :)