Many car holders are available in accessories:

https://lapmonitor.com/store/en/13-accessories

Buggy 1:10th

B6.1 Transponder holder

XB2 Transponder holder

Other 2WD examples

XB4 B74 YZ4 Transponder holder

Buggy 1:8th ECO

Mugen MXB7/8

TLR-X

Buggy 1:8th Nitro

XRAY