Another option is the Phanteks Halos units. It is a frame with lights only that can be mounted on either side of any non-lighted fan. Only dilemma is that Phanteks tends to use non-standard connectors for the light frames, but they can supply adapters for that. Only the connector mechanical details are non-standard; the electrical characteristics match standard lighting ports. NOTE that Phanteks has several such products. They have both Halos (4-pin plain RGB) and Digital Halos (3-pin ARGB ) lines, and in each there is a basic and an upscale version plus a kit that includes extra lighting strips.