I had two babies with a high need for stimulation, and I found this a tough age – mine were over the basic sensory toys for little babies, but not really able to do a shape sorter or stacker or the other slightly more complicated toys, so they were both bored and frustrated and needed a lot of entertaining. Plus they wanted to be walking but weren't quite – again, frustration, and wanting lots from me.
It does definitely get easier as their physical capabilities become more in line with their busy little brains. (And, with two, when they can play with each other, but that's a different discussion!)
In terms of making it easier now, if she likes soft play, how about baby obstacle courses? Crawl under a chair, through a big cardboard box (or buy one of those tunnels), over some cushions, etc. Chase a ball through various of the above, or just up and down the hallway. Pull all the cushions off the sofa for slightly larger-scale at home softplay. When mine were just learning to cruise the furniture, the cot was one of the easiest things to cruise – we used to having 'cruising time' when I'd pop them in the cot and chill with a book or on my phone whilst they cruised the cot.
Does she like a bath? If so, a long daytime bath just for fun is good, and obviously you have to be there and watching, but mine used to play more independently there, so at least I got a bit of a mental break. Anything that can safely get wet is a bath toy. We had random kitchen implements, old shampoo bottles, plastic animals, all sorts to keep it interesting. A washing up bowl of water in the garden on a warm day is another option – I sometimes used to put things like thin slices of lemon/orange or ice cube or edible flower petals in to mix it up a bit.
I'd also recommend baby signing – mine both liked the songs, and it definitely helped with communication before they could speak, so reduced frustration!
Does she like getting out and about? Going to groups, running errands?