A good multimeter with all necessary functions. Two minor drawbacks, both related to response time: Firstly, the continuity tester has a short delay (0.25-0.50s) before it beeps - this can be annoying when trying to analyze a device with a lot of cables, or when it is difficult to maintain contact for a long time, leading to many false negatives. The other is that autoranging takes forever to scale down low voltage/current/resistance cables, on the order of two seconds in most cases. These aren't critical points, but it's certainly a benchmark for hobbyists/enthusiasts like me who can afford to wait and/or retest in the situations described.
Upgrade Your Car Diagnostics With 16 Pin OBD2 Extension Cable Splitter - Male To Dual Female Y Cable - 50CM
17 Review
Autel AP200H OBD2 Scanner Dongle - Wireless Bluetooth Code Reader with Health Status Reports - Diagnostic Tool for Engine, Transmission, ABS, SRS - OLS/BMS Resets - All Vehicles (Android/iOS)
11 Review
Autoscanner for car diagnostics Rokodil ScanX Pro, OBD2 scanner
29 Review
MUCAR CDL20 OBD2 Scanner - Check Engine Code Reader And Diagnostic Scan Tool For All OBD II Protocol Cars Since 1996, With O2 Sensor, EVAP System, And Smog Test Functions
23 Review