Add about 3/4 of the pecans to the bottom of the slow cooker.
Break German chocolate into pieces and place over the pecans.
Add semi-sweet chocolate chips, then white almond bark on top.
Lay two paper towels across the top of the slow cooker and place the lid over them.
Cook on Low for 1 hour. Lift the lid carefully so condensation does not drip into the chocolate.
Stir until smooth. Continue cooking briefly if needed until fully melted.
Add caramel bits and stir to combine.
Spoon clusters onto parchment or wax paper.
Top with remaining pecans if desired.
Let set completely before storing.
Notes
Keep all water away from melted chocolate; even condensation can make it seize. Use the paper towel under the lid and tip the lid away from the pot when opening. Store clusters between parchment at room temperature up to 2 weeks, refrigerate up to 3 weeks, or freeze for holiday prep.