Sonic CD's soundtrack (specifically the JP/EU "Present" and "Future" tracks) relied heavily on early 90s hardware synthesizers. If a soundfont isn't enough, you can find the actual patches in VST emulations of: Libre resources for music making - Musical Artifacts
Think of it as a digital swiss army knife: you load the SoundFont into a sampler (like FL Studio's DirectWave, Logic’s EXS24, or the free Sforzando), and suddenly you have access to hundreds of instruments mapped across your keyboard. sonic cd soundfont
In recent years, there has been a resurgence of interest in Sonic CD soundfonts, driven in part by the rise of chiptune and video game music communities. Several new soundfonts have been created, including: Sonic CD's soundtrack (specifically the JP/EU "Present" and
"Community-developed have been created to replicate the timbre of the Sega CD sound hardware, allowing for the arrangement of Sonic CD compositions via standard MIDI sequencing." Several new soundfonts have been created