You can minify most of your Arduino projects using the ATtiny85, if you know how to do it properly. Here is a step-by-step guide to programming the ATtiny85 using the Arduino Uno as programmer.
STEMProjectsLab
Project: Distance Measurement Using HC-SR04 Ultrasonic Sensor
Project Overview
This project uses the HC-SR04 Ultrasonic Distance Sensor to measure the distance of an object and display that reading on a 20×4 LCD I2C screen.
How to Use Soil Moisture Sensor and NodeMCU ESP8266 with ThingSpeak IoT
This tutorial will teach you how to connect the Soil Moisture with the NodeMCU and upload the soil moisture data to the cloud using ThingSpeak.
How to Connect DHT11 with NodeMCU ESP8266 and Upload Data To ThingSpeak
This tutorial will show you how to connect the DHT11 with the NodeMCU ESP-12E and then log the data from the DHT11 to ThingSpeak.