scryfall is a excellent search engine, and it gives you the average prices in euro based on cardmarket data. So you can use it to search one specific card in one specific edition, and get to know that a 4th edition of Shivan Dragon is around 2€.
It also helps with the FBB editions (foreign black border). When a card was a reedition, but printed for the first time in a specific language, it would be with black borders instead of white. Those are more valuable for people that want black-bordered cards that are too expensive in their original black-bordered english edition, so you might want to have a special attention on these.
Scryfall also allows you to have a view by set and sort by price in euro, allowing you to see which cards are over a specific value (2€ for example). Use the "checklist" view for that, sorted by prices in euro. Here's the list of white-bordered 4th edition cards using that view.
To find the available sets, you have a specific link in the top menu.
Here's what I did lately to find the prices of my cards.
First, I did sort them by set and color in WUBRG order (white, blue, black, red, green, artifact and multiolored). This can be tricky as some sets look similar in early editions, so you may need to read a guide first. Be aware that for foreign black borders that can be trickier. For example I have a black bordered french third edition Dragon Whelp, and the card frame and template looks like an english fourth edition, except for the copyright year and the language. So trust the copyright year more than the looks on old cards if they're not in english.
Second, for each set, I go on scryfall and display a list of the cards sorted by price in euro, the more valuable first. This helps seeing immediately if you have one of the more expensive cards. Not all cards have a price displayed, so also go at the bottom of the list to see cards that may be missing a price in euro, but that could still be valuable. You can go directly on cardmarket for a more specific search for those.