Currently a number of these wasps are active in the garden. They are Sand tailed diggerwasp (Cerceris arenaria)  females.
This female is hefty and combined with her extensive yellow markings she is a striking appearance. Here she is foraging on Giant goldenrod (Solidago gigantea). Multiple specimen are active simultaneously.
I’ve caught her for identification, see here, but unfortunately she escaped during the photo session and I couldn’t find her back. After a while I saw her crawl behind the baseboard, which I tried to push up a bit so there would be space to crawl out but she didn’t. Only much later I found her crawling on the floor clearly in bad shape. Normally a bit of moisture will work wonders to get them into shape again, but in this case it did not and she passed away during the night. A pity, she has been added to the garden collection, see here.
And another female.
Also the male Cerceris arenaria  foerages every day on the Giant goldenrod (Solidago gigantea). Different specimen are active. This particular male I’ve caught for identification, see here.
References1 Nederlands Soortenregister