Many nymphs and bug-like flies do best near the bottom, or may hit the bottom at some point in the drift or swing. The snag-resistant nature of the Bouncer style makes buggy Bouncer patterns useful, but some modifications of the usual keel are often appropriate. For example, lighter mono (15-20lb test) is best for smaller hooks, and smaller beads of a darker color may give a more natural action and appearance. Non-magnetic hematite beads, usually found in a craft store or bead store, work well with nymph patterns since they are 30% lighter than brass of the same size and have a subdued shine from the black surfaces. Jade beads, some as small as 2mm, look very good and cost less than 3 cents each in a string about 16in long at a bead show. These beads are not as durable as brass (especially if you, like me, sometimes hit the gravel on a backcast), but usually last well enough. Of course, 2mm brass beads can be colored, if necessary.
The following patterns have worked well as nymphs, diving beetles, and scud-like critters.