Baader SWAN Comet Filter -

The Baader C2 SWAN-Band-Filter with ≤ 15 nm Half-Band-Width isolates the two C2 lines at 511 and 514nm.

These two emission lines, named Swan bands after their discoverer, dominate the spectrum of a comet's gas tail in the visible range. The filter allows only the light from the two carbon bands to pass through and, among other things, blocks the ubiquitous stray light, similar to a nebula filter in deep-sky observation. Structures in the gas tail thus become easier to observe, even under good observing conditions.

At the same time, this filter completely blocks the OIII line at 501nm and below, which other Swan-Band filters allow to pass. This provides even higher contrast, and comets with gas tails can be more easily distinguished from those dominated by a dust tail

IDAS LPS-D3 Filter -

The IDAS LPS-D3 filters enhance the contrast of astronomical emission nebulae against a sky with both man-made and natural* sky glow sources, yet preserve the colour balance of broadband objects such as galaxies. As with other IDAS interference filters, the bandpasses are designed to accommodate the steep ray angles of fast optical systems.

Askar Colourmagic HA/OIII  & SII/OIII 6nm -

The filter enables the capture of the three main emission nebulae bands using two diffent filters, whilst suppressing unwanted light pollution. It enables you to capture cleaner data and reduces the post processing efforts to isolate faint details from the background light pollution.

These use of these filters will allow you to HOS palette & enhance your standard broadbands images with increased H2 regions etc - What's not to like with that :)