For a Rundkopf-Jig search, the two WS Baits - handgemachte Gummifische & Gummiköder Jighaken 1/0 Rundkopf Jig listings are the most direct match: they’re made for soft plastics and are described for Zander, Hecht und Barsch. The price range is also very low, which makes them a practical choice if you want multiple weights.
Jigfreak Rundkopf-Jig 0/1 VMC 7249 Haken is a good hook-focused option if you want a sharp, stable round-bend jig hook for soft bait rigs.
Delalande Pêche - Leurres souples MICRO RUND JIGKOPF BARBLESS fits when you want a classic round-head jig for light presentations, especially with smaller soft baits and a barbless setup.
Switch to a heavier jig or a different head style if you need faster bottom contact in deeper water or stronger current. Move to a weedless rig if you’re fishing heavy cover. If fish are chasing higher in the water column, a swimbait, spinnerbait, or shallow-running lure may outfish a round-head jig.