Below is a list of all OEM and high quality YPbPr/RGB third party cables available for the original Xbox.
RF Modulator
- RF Adapter
- Part number: X08-25285.
Composite
- Standard AV cable
- Part number: X08-47696.
- Same thing as what was packaged with the console.
- Standard AV cable (European version)
- Part number: X08-25071.
- Same as X08-47696, but packaged with an additional composite RCA to SCART adapter.
S-Video
- Advanced AV Pack
- Part number: X08-47698.
- A breakout box with female RCA composite and S-Video output, in addition to an S/PDIF audio output.
RGB
- Advanced SCART Cable
- Part number: X08-25275.
- Also features S/PDIF audio output.
- Somewhat uncommon.
- PACKAPUNCH Cable (SCART RGB)
- Should do the same functions as the official one, aside from optical audio.
- Can be purchased with either composite sync or CSYNC.
YPbPr
- High Definition AV Pack (Breakout box)
- Part number: X08-25301.
- This is similar to the Advanced AV Pack, but replaces the composite video output with YPbPr.
- Somewhat uncommon
- High Definition AV Pack (Cable)
- Part Number: X08-53570-01.
- SKU: K03-00007
- This is a newer equivalent to the X08-25301 where the RCA cables and S/PDIF output are connected directly to the AV connector, like the Xbox 360's HD AV cable.
- Somewhat uncommon
- Monster GameLink 400X
- Direct AV to YPbPR cables, just like the X08-53570-01. However, they don't have a built-in S/PDIF connector like Microsoft's cables. You need an additional GameLink 100X adapter in order to add optical audio output.
- Psyclone branded component video cables
- Another cable similar to X08-53570-01, but the optical audio port is built into the cable, unlike the Monster cable.
- Official Xbox 360 component cables, but modified to have the AVIP connector for an original Xbox.
- Cheapest solution for high quality component cables, but will be very time-consuming to DIY. You may be able to find pre-made cables sold in your region.
- US Reseller
- eBay Reseller (USA)
- A nice aftermarket shell exists for this solution, which includes a method of using the optical audio output from the original connector.
- PACKAPUNCH Cable (SCART YPbPr)
- Has to be requested during purchasing if you're using it with devices like a OSSC or RetroTink.
- XOSVP
- Free & open source equivalent to the X08-25301.
- Does not feature RCA audio output in the design, but the optical output with a DAC will have better sound quality anyway, in addition to having surround sound support.
- There also seems to be a modified version(?) of the XOSVP being sold on eBay as the "XBHDA".
- XEDUSA (Original)
- Homebrew alternative to the X08-25301, although this one does not have an open source design. In addition to having YPbPr, it also has optical audio outputs through S/PDIF and a COAX connector (yellow RCA output).
- Not sold anymore.
- XEDUSA+
- Just like the XEDUSA, but also added an HDMI output, and is still currently sold.
- VEDUSA+
- Just like the XEDUSA+, but has an RGBHV/RGBS VGA port in-place of the XEDUSA+'s HDMI port.
- Neoya X2VGA
- "X2VGA High Definition VGA Pack"
HDMI
More info can be found on the HDMI Output page.