If you are going to Ljubljana the first tour that I highly recommend is the LjubljanaNjam Food Walk. Slovenia is one of the up and coming food regions in the world and Ljubljana is at the forefront of that movement. Iva is the main guide in the food walk (but works with a team in the busy season). Iva knows the food scene in Ljubljana better than anyone and will give you a great overview of the culture of the city through tasting of its modern cuisine. Hanging out with Iva feels very much like spending time with a friend as she is warm and very friendly (as well as a wealth of information about all things food in Slovenia). I've done two tours with her and have tasted things from more traditional foods (with a modern twist) like soup and dumplings, to things like frog legs and ceviche. She keeps her tours small so that she can cater a bit to the group (you can request a food walk, or ones more focused on coffee, wine, desserts or beer). The walk is around 55€ per person (sometimes more sometimes less depending on what you request) which covers all of the food (and Iva's time) and lasts for several hours (ours was about 4 hours). Iva is really good about responding to email and making it work with the times you are available (if you contact her in advance), or if you didn't plan in advance enough she is often willing to accommodate you in a tour she is already running. I highly recommend a tour with her, you will not be disappointed.
The second tour I recommend is the Ljubljana Graffiti Tour. Sandi was my tour guide (he does most of the tours but works with a team during the busy season). He is incredibly knowledgeable about the different styles of graffiti (for his PhD he is researching graffiti) and on the tour he teaches you not just about the graffiti but about the political and social statements that the graffiti is making. The tour is a unique way to get a history of the city. I've been to Ljubljana a bunch of times and he took me to really interesting parts of the city that I had ever seen (or even heard of) before. The walk is free but tips are (pretty much) expected and very much appreciated. You can reserve your spot on the Ljubljana graffiti tour through the website.