A common recommendation for those starting to publish in academic journals is try to go for the journal you read the most. Of course this could mean a highly competitive journal, in which case you may need to consider other options, but the idea behind this advice is that by reading papers from a journal you get familiar with its style, purposes and so on and, therefore, all this would reflect in your paper.
When I heard this advice my computer programmer brain thought: I could write a script to do this for me!
Since I use Zotero and Zotero is a very friendly open source software, I decided to try to write a script in Python that would search its database. After checking the tables, I could identify where the information I needed was (see the query below).
SELECT * FROM itemData INNER JOIN itemDataValues ON itemData.valueID=itemDataValues.valueID WHERE fieldID=12 ORDER BY value
For those interested: 12 is the id for the "publication" field, which contains the title of the journal for "journal article" items.
You can use the query above in any software that can read SQLite (I recommend SQLiteBrowser on Linux). But if you are not experienced with such things, you can just download the script available on my github or here (this link may be outdated).
After unzip it, you will get a .py file. Save it on main Zotero's folder (you will see a zotero.sqlite file in it) and run the script. It depends on some very basic Python library, which I believe are installed in most computers being regularly used. The screenshot below shows the result.
Now, you just need to scroll the list and find the most common journal in your library (pay attention to small variations in the title of the journal - the script is sensitive to them). For me, it was the Educational Studies in Mathematics.