The Grove Beginner Kit for Arduino is one of the best kits for beginners to get started with Arduino. No troublesome soldering and no complicated wiring. You can focus on learning Arduino. This kit includes a main control board Seeeduino Lotus and 8 Grove modules, which covering sensor, actuator and display. All you need to do is following the demo, plug the module into the Seeeduino Lotus, truly plug and play.
Part List:

Seeeduino Lotus v1.1
Grove – Tilt Switch
Grove – Buzzer
Grove – Temperature & Humidity Sensor (DHT11)
Grove – 3-Axis Digital Accelerometer
Grove – Light Sensor
Grove – Line Finder
Grove Chainable RGB LED
Grove – 16 x 2 LCD (White on Blue)

Resources:

Wiki

More Sensors and Accessories:

20 Modules in 1 Box
30 Modules in 1 Box
40 Modules in 1 Box

Available Arduino Boards:

Arduino UNO R3 Clone
Arduino MKR Zero with Headers
Arduino MKR FOX 1200
Arduino MKR WAN 1300 (LORA Connectivity)
Arduino Nano Every (headers) ATMega4809
Arduino Nano Every ATMega4809
Arduino MKR Motor Carrier/Controller/Driver
Arduino MKR RGB Shield
Arduino MKR Environmental Shield
Arduino MKR THERM Shield