My son got these foam blocks for his 1st birthday. He's loved them so far although they don't interlock. There are lots of similar products out there, some have Velcro and some don't. Here's a random one with a tunnel.

Then there's tunnel sets like this.

Then there's jungle gyms of all sorts and sizes. Big and small, plastic and wooden. example 1///example 2///example 3///example 4///example 5

I've never seen something I would describe as a mini play place though. To be honest, it sounds expensive and like it would take up a lot of room, even the "mini" version. The only thing I'd consider close would be those big, expensive backyard playsets like these. I did find some companies that make them like this or this or this but they're all designed for commercial spaces and either require you to call and get a quote or are very expensive. It's bc they're designed for very different things. A slide made for 1 or 2 toddlers to enjoy on occasion is very different from a slide that had to stand up everyday to 100s of kids of different sizes, many of whom don't use the slide "properly," not to mention that when it's in a public spacee then the owner of that slide is no longer just worried about their own kid but also about being legally responsible for all those 100s of other kids. Compare a playground toddler slide to a little tikes slide and you'll immediately see the quality difference. In other words, the affordable playground equipment is also going to be simpler, smaller, and less sturdy. Maybe they cost less when your grandpa got them or maybe he got lucky and was able to snag some used stuff?