Slides Go is another great place for slides themes. They organise their templates a little differently than Slides Carnival and I am still exploring this awesome resource. So far, my favourites are Bokeh Lights and Watercolor Texture.
Procreate is my favourite drawing app. It does cost around $10.00, but for me it is worth it. To see some of the art I've created using Procreate, click here.
Notability is my go to app for taking notes, making annotations, and recording things for professional development. It also costs around $10, and lets you create new docs (with a variety of paper backgrounds, grid is my favourite), mark up PDFs, add gifs and images, highlight, draw, and so much more. I often export these as PDFs and put them online for my students.
Skitch is a free app that I often use to make annotated version of stories. It cannot work with PDFs, but is great for marking up pictures of texts.