Proverbs 15:26:
The LORD detests the thoughts of the wicked,
but those of the pure are pleasing to him.
Mark 7:20-22
20He went on: "What comes out of a man is what makes him 'unclean.' 21For from within, out of men's hearts, come evil thoughts, sexual immorality, theft, murder, adultery, 22greed, malice, deceit, lewdness, envy, slander, arrogance and folly.
Ephesians 2:1-10
1As for you, you were dead in your transgressions and sins, 2in which you used to live when you followed the ways of this world and of the ruler of the kingdom of the air, the spirit who is now at work in those who are disobedient. 3All of us also lived among them at one time, gratifying the cravings of our sinful nature[a] and following its desires and thoughts. Like the rest, we were by nature objects of wrath. 4But because of his great love for us, God, who is rich in mercy, 5made us alive with Christ even when we were dead in transgressions—it is by grace you have been saved. 6And God raised us up with Christ and seated us with him in the heavenly realms in Christ Jesus, 7in order that in the coming ages he might show the incomparable riches of his grace, expressed in his kindness to us in Christ Jesus. 8For it is by grace you have been saved, through faith—and this not from yourselves, it is the gift of God— 9not by works, so that no one can boast. 10For we are God's workmanship, created in Christ Jesus to do good works, which God prepared in advance for us to do.
Hebrews 4:12
For the word of God is living and active. Sharper than any double-edged sword, it penetrates even to dividing soul and spirit, joints and marrow; it judges the thoughts and attitudes of the heart.
James 2:4
have you not discriminated among yourselves and become judges with evil thoughts?
These passages I have provided gives the assumption that thoughts and immaginaton are kind of the same thing, and it can be both good and evil. If there are evil thoughts and desires, then there must be good, no? There cannot be a dark without a light and a light without a dark. The darkness proves the light.
The thoughts, heart and tongue are closely related to each other - like an interpersonal relationship - what one's thoughts are are fueled by their heart and vise versa. What someone says mirrors what is in the heart.
Hope this adds something to the discussion.