ListMerger

ListMerger is about as simple as this pack gets: hand it two lists, get back one merged list. The README's own summary is a single line - "merge multiple image lists into a single batch" - and the node itself ships with no further in-graph description, so what follows is what the schema and that one sentence actually tell you, not more.

It's one of the smaller utilities inside ComfyUI-WJNodes, a large personal pack from GitHub user 807502278 that mostly handles cropping, video slicing, and color work - ListMerger is the plumbing that occasionally sits between those bigger pieces.

How it works

Connect two lists to list1 and list2 and it outputs a single combined merged_list. There's also an is_last toggle whose exact behavior isn't documented beyond its name - the reasonable read is that it's meant for chaining multiple ListMerger nodes together to combine more than two lists (feed one merge's output into the next node's list1, and flag the final node in the chain with is_last), but that's an inference from the input's existence, not a confirmed mechanic. Test it in a small graph before depending on it for anything more than two lists.

The inputs and outputs that matter

• list1 / list2 - the two lists to combine, both typed * (any), so this isn't strictly limited to images despite the README's "image lists" framing - whatever list type you connect, it should merge.
• is_last (default off) - undocumented beyond its name. Likely relevant only if you're chaining several ListMerger nodes to combine more than two lists at once.

Output is a single merged_list.

How to install it

Via ComfyUI Manager, search "ComfyUI-WJNodes." Manually:

cd ComfyUI/custom_nodes
git clone https://github.com/807502278/ComfyUI-WJNodes.git

Restart ComfyUI. No models needed - this is list concatenation, nothing more.

Common issues & troubleshooting

Merged list doesn't contain everything you expected. Since this node's behavior isn't documented beyond a one-line summary, the safest way to confirm it's doing what you think is to check the output length or contents directly (a preview or debug node) rather than assuming standard list-concatenation semantics.

Chaining multiple ListMerger nodes for more than two lists gives unexpected results. This is the part the pack doesn't explain - is_last exists but its exact effect isn't spelled out anywhere. If you need to merge three or more lists reliably, test the chained approach on a small, easily-verified example (a handful of images you can count) before trusting it on a real batch.

Wrong data type coming out. Because both inputs accept *, it's easy to accidentally wire in something other than an actual list - double-check the upstream node is genuinely producing a list output, not a single item, before troubleshooting this node itself.

Nowhere further to check. This is one of the least-documented nodes in an already low-profile personal pack - beyond the schema and the one-line README description, there's no deeper source to consult. This is a genuine gap worth flagging rather than guessing past.