Parts of MSDOS can be found in a few places. Combined they make the whole thing.
Win98 can make a DOS boot disk for you, which contains vital files like command.com, autoexec.bat, MSCDEX.exe, format.exe, etc. It's got Win98 trimmings on it, but it's all from DOS 6.21/6.22. You can also download boot disks from various places.
On the Win98 disc itself you can find other utilites like deltreee, emm386, xcopy, xcopy32, and so on.
Also, if you want to go hardcore you can find all the key DOS files in the BASE5.CAB file, also located on the Win98 disc, in the Win98 folder. It's not organized, but it has everything you need.