I would recommend Language Transfer. Their website is https://www.languagetransfer.org. They also have a Youtube channel. They offer courses in French, Swahili, Italian, Greek, German, Turkish, Arabic, Spanish, and English for Spanish speakers.
Some of their courses are works in progress, but I know the Spanish, Swahili, Greek, and German courses are complete. I listened to their Spanish course and was impressed. They don't just have you mindlessly memorizing and regurgitating words. I felt like I actually understood sentence structure and verb conjugations by the time I finished the course, and the instructor made it interesting. They emphasize learning grammar and structure over vocabulary, so you might want to use a website like Duolingo as a supplement. Don't get me wrong, you still learn plenty of vocabulary and the ability to figure out a lot of words based on English.
I can't speak about any of their other courses since I haven't taken them, but the Spanish course is a winner in my opinion.